Cementless alumina-on-alumina total hip arthroplasty in patients younger than 50 years: a 5-year minimum follow-up study

Periprosthetic Occult Femoral Fracture: An Unknown Side Effect of Press-Fit Fixation in Primary Cementless Total Hip Arthroplasty

Purpose

The objectives of this study were to examine the prevalence and risk factors for development of periprosthetic occult femoral fractures during primary cementless total hip arthroplasty (THA) and to assess the clinical consequences of these fractures.

Materials and Methods

A total of 199 hips were examined. Periprosthetic occult femoral fractures were defined as fractures not detected intraoperatively and on postoperative radiographs, but only observed on postoperative computed tomography (CT). Clinical, surgical, and radiographic analysis of variables was performed for identification of risk factors for periprosthetic occult femoral fractures. A comparison of stem subsidence, stem alignment, and thigh pain between the occult fracture group and the non-fracture group was also performed.

Results

Periprosthetic occult femoral fractures were detected during the operation in 21 (10.6%) of 199 hips. Of eight hips with periprosthetic occult femoral fractures that were detected around the lesser trochanter, concurrent periprosthetic occult femoral fractures located at different levels were detected in six hips (75.0%). Only the female sex showed significant association with an increased risk of periprosthetic occult femoral fractures (odds ratio for males, 0.38; 95% confidence interval, 0.15-1.01; P=0.04). A significant difference in the incidence of thigh pain was observed between the occult fracture group and the non-fracture group (P<0.05).

Conclusion

Occurrence of periprosthetic occult femoral fractures is relatively common during primary THA using tapered wedge stems. We recommend CT referral for female patients who report unexplained early postoperative thigh pain or developed periprosthetic intraoperative femoral fractures around the lesser trochanter during primary THA using tapered wedge stems.

Preventing ceramic liner fracture after Delta ceramic-on-ceramic total hip arthroplasty

BACKGROUND

The results of total hip arthroplasty (THA) with use of Delta ceramic articulation were successful at medium term follow-up. The use of this newest ceramic has markedly reduced the incidence of ceramic head fractures, but not the incidence of ceramic liner fractures. We tested a hypothesis that the ceramic fractures are prevented by use of a metal shell with 18° inner taper angle and a stem design with a reduced neck geometry.

METHODS

We conducted a prospective multicenter study of cementless THA with use of 32/36-mm Delta ceramic bearing, Exceed ABT metal shell and Taperloc stem. We evaluated ceramic fracture, noise, clinical results, radiological changes and survival rate at a minimum of 5-year follow-up.

RESULTS

From April 2010 to February 2012, 246 patients (274 THAs) were enrolled. Among them, 224 patients (130 men and 94 women, 250 hips) were followed-up for 5-8 years (mean 6.0 years). Ceramic malseating or fracture did not occur in any patient. Eight patients (8 hips, 3.2%) reported noise. Mean Harris hip score was 84 points at the latest follow-up. All acetabular and femoral components had bone-ingrown stability. Two hips were revised due to recurrent dislocation and periprosthetic fracture. The survival rate was 99.6% at 8 years postoperatively.

CONCLUSION

Ceramic fractures can be prevented by a use of (1) 32/36-mm Delta ceramic bearing, (2) metal shell with 18° taper angle, and (2) stem with a reduced neck geometry. However, noise remains a concern of the Delta ceramic bearing.

LEVEL OF EVIDENCE

Therapeutic level II.

No Clinically Important Differences in Thigh Pain or Bone Loss Between Short Stems and Conventional-length Stems in THA: A Randomized Clinical Trial

BACKGROUND

Short-length stems were developed to reduce bone loss of the proximal femur and potentially decrease the incidence of thigh pain after cementless THA. However, it remains unknown whether short stems indeed reduce bone loss or the frequency of thigh pain.

QUESTIONS/PURPOSES

Is there a difference between short- and standard-length stems in terms of: (1) the frequency or severity of thigh pain, (2) modified Harris hip scores, (3) implant loosening, or (4) bone mineral density as measured by dual-energy x-ray absorptiometry?

METHODS

Between March 2013 and January 2014, three surgeons performed 205 primary THAs. To be eligible, patients needed to be at least 20 years of age, have not undergone previous history of hip surgery, and have no metabolic bone disease. A total of 100 patients were randomized to receive THA either with a short stem (n = 56) or with a standard-length stem (n = 44). Both stems were proximally coated, tapered, cementless stems. Compared with standard stems, short stems typically were 30- to 35-mm shorter. A total of 73% (41 of 56) and 77% (34 of 44) of those groups, respectively, were accounted for at a minimum of 5 years and were analyzed. The presence of thigh pain during activity was evaluated using a 10-point VAS, and the modified Harris hip score was calculated by research assistants who were blinded to the treatment groups. Plain radiographs were taken at 6 weeks, 6 months, and 12 months postoperatively, and every 1 year thereafter; loosening was defined as subsidence > 3 mm or a position change > 3° on serial radiographs. Radiological assessment was performed by two researchers who did not participate in the surgery and follow-up evaluations. Bone mineral density of the proximal femur was measured using dual-energy x-ray absorptiometry at 4 days, 1 year, 2 years, and 5 years postoperatively. The primary endpoint of our study was the incidence of thigh pain during 5-year follow-up. Our study was powered at 80% to detect a 10% difference in the proportion of patients reporting thigh pain at the level of 0.05.

RESULTS

With the numbers available, we found no difference between the groups in the proportion of patients with thigh pain; 16% (9 of 56) of patients in the short-stem group and 14% (6 of 44) of patients in the standard-stem group experienced thigh pain during the follow-up period (p = 0.79). In all patients, the pain was mild or moderate (VAS score of 4 or 6 points). Among the 15 available patients who reported thigh pain, there was no difference between the implant groups in mean severity of thigh pain (4.3 ± 0.8 versus 4.2 ± 0.7; p = 0.78). There were no between-group differences in the short versus standard-length stem groups in terms of mean modified Harris hip score by 5 years after surgery (89 ± 13 versus 95 ± 7 points; p = 0.06). No implant was loose and no hip underwent revision in either group. Patients in the short-stem group showed a slightly smaller decrease in bone mineral density in Gruen Zones 2, 3, and 5 than those in the standard-stem group did; the magnitude of the difference seems unlikely to be clinically important.

CONCLUSION

We found no clinically important differences (and few differences overall) between short and standard-length THA stems 5 years after surgery in a randomized trial. Consequently, we recommend that clinicians use standard-length stems in general practice because standard-length stems have a much longer published track record in other studies, and short stems can expose patients to the uncertainty associated with novelty, without any apparent offsetting benefit.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Incidence of Ceramic Fracture in Contemporary Ceramic-on-Ceramic Total Hip Arthroplasty: A Meta-analysis of Proportions

BACKGROUND

We performed a proportion meta-analysis of currently available data to determine the prevalence of ceramic fracture for each generation.

METHODS

A total of 10,571 total hip arthroplasties from 45 studies were included. Proportion meta-analysis with a random-effects model was performed to estimate the prevalence of ceramic fracture. To determine whether the ceramic fractures have a fatigue nature and a risk or latent period for the development, postoperative time lapse, patient age, and body mass index were related with ceramic fracture by metaregression analysis.

RESULTS

As of postoperative 2.0 to 18.8 years, the rate of ceramic fracture was 0.5% (95% CI, 0.3%-0.8%) in the forte group and 0.2% (95% CI, 0.1%-0.4%) in the delta group (P = .059). The ceramic fracture rate for each component was 0.2% (95% CI, 0.1%-0.3%) for the forte head, 0.1% (95% CI, 0.0%-0.2%) for the delta head (P = .210), 0.2% (95% CI, 0.1%-0.3%) for the forte liner, and 0.2% (95% CI, 0.1%-0.4%) for the delta liner (P = .305). The rate of ceramic fracture per 1000 patient-years was 0.9 (95% CI, 0.5-0.13) in the forte group and 0.5 (95% CI, 0.2-0.8) in the delta group (P = .072). In metaregression analysis, no significant associations were found between prevalence of ceramic fracture and postoperative time lapse, patient age, or body mass index.

CONCLUSIONS

The rate of ceramic fracture was 0.9/1000 patient-year in the forte group and 0.5/1000 patient-year in the delta group. The results of this study provide baseline data for further studies validating ceramic bearings.

LEVEL OF EVIDENCE

Level I, meta-analysis.

Highly Cross-Linked Polyethylene in Total Hip Arthroplasty in Patients Younger Than 50 Years With Osteonecrosis of the Femoral Head: A Minimum of 10 Years of Follow-Up

BACKGROUND

Polyethylene wear and subsequent periprosthetic osteolysis remain a major concern of total hip arthroplasty (THA) failure in young, active patients with osteonecrosis of the femoral head (ONFH). The literature is lacking regarding the long-term performance of highly cross-linked polyethylene (HXLPE) in these patients. The purpose of this study is to evaluate long-term results for cementless THA using metal-on-HXLPE bearing couplings in patients younger than 50 years with ONFH.

METHODS

We retrospectively evaluated the clinical and radiographic results of a consecutive series of 85 THAs (in 67 patients) performed with HXLPE liners (Durasul) in patients younger than 50 years who had ONFH. All procedures were performed at a single institution by a single surgeon using the same type of implants. The minimum duration of follow-up was 10 years (mean, 13.5 years; range, 10-17.3 years). Wear was measured using computer software. Osteolysis was evaluated with the use of radiography and computed tomography.

RESULTS

The mean Harris hip score was 49.3 points (range, 26-68 points) before surgery, which improved to 93.6 points (range, 87-98 points) after surgery. Neither femoral nor acetabular components displayed mechanical loosening, and no components had been revised by the final follow-up evaluation. Radiographs and computed tomography scans did not demonstrate osteolysis. The mean liner wear was 0.037 mm/y (range, 0-0.099 mm/y). With the data available, univariate regression analysis did not demonstrate that age, sex, weight, activity level, underlying cause of osteonecrosis, liner thickness, or cup inclination had any influence on liner penetration.

CONCLUSION

Although the long-term effects of HXLPE particles remain unknown, the implant survivorship rate and wear rate in our study are promising and support the continued use of metal-on-HXLPE bearing couplings in these high-risk patients because they do not produce any of the issues associated with hard-on-hard couplings.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Occult periprosthetic femoral fractures occur frequently during a long, trapezoidal, double-tapered cementless femoral stem fixation in primary THA

The present study aimed to investigate the prevalence and clinical consequences of occult intra-operative periprosthetic femoral fractures in total hip arthroplasty (THA). Between 2012 and 2017, a total of 113 primary THAs were enrolled. The mean age of the patients was 66.4 ± 7.6 years. We assessed occult intra-operative periprosthetic femoral fractures with the use of computed tomography (CT) and risk factors, including age, sex, body mass index, diagnosis, stem size, and radiographic parameters of proximal femoral geometry were analyzed. We also assessed the differences in thigh pain and stem subsidence and alignment between the patients with and without occult periprosthetic femoral fracture. Occult intra-operative periprosthetic femoral fractures were found in 13 of 113 hips (11.5%). In 9/13 (69.2%) of occult fractures, fracture lines were started from the region below the tip of the lesser trochanter. Six periprosthetic femoral fractures (5.3%) were found during the operation. Out of the five hips that had detected femoral fractures around the lesser trochanter intra-operatively, four hips (80%) showed concurrent occult fractures on different levels. The female sex (P = .01) and canal filling ratio at 7 cm below the tip of the lesser trochanter (P = .01) were significantly different between the patients with and without occult periprosthetic femoral fracture. The sex was significantly associated with an increased risk in predicting an occult intra-operative periprosthetic femoral fracture (odds ratio of male, 0.25 compared with the female; 95% CI, 0.08-0.85; p = .02). There was a significant difference in the incidence of thigh pain between occult fracture group and non-occult fracture group (P < .05). There were no significant differences in stem subsidence and alignment between the patients with and without occult periprosthetic femoral fracture. All 13 cases of occult intra-operative periprosthetic femoral fractures were healed at the final follow-up. Occult periprosthetic femoral fractures are common during a long, trapezoidal, double-tapered cementless femoral stem fixation in primary THA, that CT scans are helpful to identify them, and that these fractures do not adversely affect the implant's survival if a rigid fixation of the implants has been achieved.

Relationships between the femoral neck-preserving ratio and radiologic and clinical outcomes in patients undergoing total-hip arthroplasty with a collum femoris-preserving stem

The femoral neck-preserving ratio is crucial in arthroplasty with a collum femoris-preserving (CFP) stem. The aim of our study was to analyze the relationships between the neck-preserving ratio and the short-term radiologic and clinical outcomes of patients who underwent total-hip arthroplasty (THA) with a CFP stem.The data of 325 hips from January 2015 to December 2016 were retrospectively reviewed. The demographic and radiologic data before and after surgery were obtained from patients. The neck-preserving ratio was defined as the ratio of the preserved femoral neck length to the preoperative femoral neck length. Correlations between the neck-preserving ratio and the radiologic and clinical outcomes of patients were analyzed.The mean neck-preserving ratio was 66.38 ± 6.91% in the current study. We divided patients into 3 groups according to the neck-preserving ratio: group A (neck-preserving ratio ≤60.00%), group B (60.00% < neck-preserving ratio < 70.00%), group C (neck-preserving ratio ≥70.00%). Radiologic features, including the neck-shaft angle ratio (0.96 ± 0.05), canal fill ratio (0.64 ± 0.07), anterior-posterior offset ratio (1.04 ± 0.10), and lateral offset ratio (2.55 ± 1.56) (ratios of the postoperative values to the preoperative values), and the prevalence of complications was significantly different among the groups (χ = 21.173, P < .001). In the correlation analysis, we found a moderate negative correlation between the neck-preserving ratio and neck-shaft angle ratio (r = -0.308, P < .001) and a slight positive correlation of the neck-preserving ratio with the anterior-posterior offset ratio (r = 0.415, P < .001) and the lateral offset ratio (r = 0.164, P = .003). In the linear regression analyses, the neck-preserving ratio was significantly linearly correlated with the neck-shaft angle ratio (B = -0.232, 95% confidence interval [CI] = -0.311 to -0.154, P < .001), anterior-posterior offset ratio (B = 0.589, 95% CI = 0.447-0.730, P < .001), and lateral offset ratio (B = 3.693, 95% CI = 1.256-6.131, P = .003). However, there was no significant linear correlation between the neck-preserving ratio and the canal fill ratio (B = 0.073, 95% CI = -0.033 to 0.180, P = .174). Logistic regression analyses also showed that a sufficient neck-preserving ratio was a protective factor for periprosthetic femoral fractures (odds ratio [OR] = 0.924, 95% CI = 0.859-0.994, P = .035), dislocations (OR = 0.892, 95% CI = 0.796-0.999, P = .048), and thigh pain (OR = 0.886, 95% CI = 0.818-0.960, P = .003).For CFP stems, an insufficient neck-preserving ratio is significantly correlated with poor radiologic and clinical outcomes. Therefore, surgeons should be cognizant to preserve a sufficient femoral neck length during surgery to improve the outcomes for patients undergoing THA with CFP stems.

Could larger diameter of 4th generation ceramic bearing increase the rate of squeaking after THA?: A retrospective study

The present study aimed to evaluate the clinical outcomes and bearing-specific complications in a single center of 135 delta ceramic-on-ceramic (COC) total hip arthroplasties (THAs) and explore the occurrence rate of squeaking in 4th generation COC THAs and collate the risk factors for squeaking.We retrospectively analyzed consecutive cohorts of 127 patients (135 hips) who had primary THA with delta COC bearings in our hospital between April 2010 and April 2012. Preoperative Harris hip score (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and University of California Los Angeles (UCLA) activity score were evaluated preoperatively and postoperatively. We also evaluated ceramic fracture, squeak, mid-term results, and survival.In our study, the final patient final follow-up date was July 31, 2016. The mean preoperative HHS improved from 39.5 to 93.1 points. Mean preoperative UCLA score was 3.2 points, improving to 8.2 points. The mean preoperative total WOMAC score was 55.5 points and the mean total WOMAC score was 13.3 points at the final follow-up. The Kaplan-Meier survival plot of revision for any reason as the end point was 98.5% and survival with ceramic fracture as the end point was 99.2% at a mean of 70 months' follow-up. One post-operative ceramic liner rim fracture occurred at 50 months after surgery. Thirteen of the 135 hips produced a squeaking sound. There were no significant differences in gender (P = .56), age (P = .20), body mass index (BMI) (P = .11), diagnosis (P = .46), cup inclination (P = .36), or cup anteversion (P = 1.0) between the squeaking and non-squeaking groups. However, the incidence of squeaking in the 36 mm COC femoral head bearings was higher than in the 28 mm size (13.6% vs 2.1%, P = .033).The 4th generation COC bearing performed well and provides an encouraging rate of survival with no osteolysis or loosening. However, we found that a squeaking sound associated with use of the delta ceramic occurred at a rate of 9.6%, with the larger-diameter heads having significantly higher incidence.

Total hip arthroplasty using a monobloc cementless femoral stem for patients with childhood Perthes’ disease

Aims

Modular or custom-made femoral components have been preferred for total hip arthroplasty (THA) in patients with a history of Perthes’ disease because of the distortion in the anatomy of the proximal femur. However, it has not been established whether a monobloc cementless stem will fit the distorted proximal femur or whether the results of the procedure are satisfactory in this group of patients.

Patients and Methods

We reviewed 68 consecutive patients who had undergone THA for childhood Perthes’ disease between June 2003 and December 2008. There were 35 men and 33 women with a mean age of 48 years (16 to 73) at the time of index arthroplasty. Their mean body mass index was 24.4 (18.3 to 32.9). Of the 68 hips, 32 were classified as Stulberg class III and 36 as class IV. The mean pre-operative shortening of the affected leg was 17.2 mm (5 to 34). The minimum follow-up was five years (mean 8.5 years; 5.2 to 10).

Results

An intra-operative calcar fracture occurred in eight hips (11.8%) and was successfully treated by cerclage wiring. The mean stem version was 14.6° (-2.3 to 30; standard deviation (sd) 7.3). The mean acetabular component abduction was 40.2° (23.7 to 56.0; sd 6.5) and the mean anteversion 28.3° (6.4 to 43.0; sd 7.6), respectively. The mean follow-up was 8.5 years (5.2 to 10). No dislocations occurred and no hips were revised during the course of the study. At final follow-up, the mean Harris Hip Score was 91 points (59 to 100) and the mean University of California, Los Angeles activity score was 3.2 (2 to 8).

Conclusion

Monobloc cementless stems reliably restore the anatomy in Perthes’ disease at THA without the need for custom-made or modular implants. Cite this article: Bone Joint J 2017;99-B:440–444.

Metal on Metal or Ceramic on Ceramic for Cementless Total Hip Arthroplasty: A Meta-Analysis

BACKGROUND

Hard bearings, metal on metal (MOM) and ceramic on ceramic (COC), have been developed to overcome polyethylene wear-related osteolysis, but comparisons between these 2 hard bearings are limited. We performed a meta-analysis to determine revision rates for (1) any reason, (2) aseptic loosening, (3) periprosthetic joint infection (PJI), and (4) recurrent dislocation between MOM and COC bearings in cementless total hip arthroplasty.

METHODS

This analysis included 3 studies comparing COC and MOM bearings and 56 studies reporting outcomes of MOM or COC bearings. We conducted a comparison meta-analysis (with a fixed-effects model) on the 3 comparative studies and a proportional meta-analysis on the data from the 59 articles to determine a consensus.

RESULTS

In the comparison meta-analysis, MOM showed higher revision rate than COC for any reason (odds ratio = 2.39, P = .046) and PJI (odds ratio = 6.21, P = .015). In the proportion meta-analysis, the MOM group showed significantly higher revision rate than COC group for any reason, aseptic loosening, and PJI.

CONCLUSION

MOM bearings were associated with a higher risk of revision for any reason and PJI than COC bearings after cementless total hip arthroplasty.

Frequency, Developing Time, Intensity, Duration, and Functional Score of Thigh Pain After Cementless Total Hip Arthroplasty

BACKGROUND

Although thigh pain is an annoying problem after total hip arthroplasty (THA), little information has been known about its natural course.

METHODS

To determine the frequency, time of onset, and duration of thigh pain after cementless THA, we evaluated 240 patients (240 hips) who underwent primary THA because of femoral head osteonecrosis with the use of a single tapered stem.

RESULTS

Twenty-seven patients (11.3%) experienced thigh pain during the follow-up of 3-11 years (mean, 84 months). The pain developed 2-78 months (median, 25 months) after THA. The 75% of pain developed within 36 months. In 25 patients, the pain disappeared postoperatively 1 month-64 months (mean, 17.4 months), and 2 patients (7.4%, 2/27) had persistent thigh pain. There were no differences in the latest Harris Hip Score between the thigh pain group and no thigh pain group.

CONCLUSION

Our results provided basic information about the natural history of thigh pain after cementless THA with a tapered stem design.

The Survival Analysis in Third-Generation Ceramic-On-Ceramic Total Hip Arthroplasty

A total of 527 patients (577 hips) who underwent primary THA using third-generation ceramic-on-ceramic (CoC) articulation were retrospectively reviewed. They were followed up for an average of 5.9 years. Seven hips experienced liner fracture and 14 hips experienced head fracture. Squeaking occurred in eight hips. The revision rate in this study was 5.2%, but excluding the cases of ceramic head and liner fracture, there were nine cases (1.6%) of revision surgery. Considering revision for any reason as the end point, mean survivorship was 93% at 10 years. According to the femoral head size and neck length, 28 mm head with short neck has the worst survivorship of 89% at 10 years. Overall, our study showed a higher rate of ceramic fracture compared with other studies.

Third-generation alumina-on-alumina total hip arthroplasty: 14 to 16-year follow-up study

Ceramic-on-ceramic articulation has the lowest wear with little osteolysis. However, the wear and osteolysis in long-term follow-up are not known. Another concern is ceramic fracture, which might occur after repeated stress during a long period. Ninety hips (76 patients with a mean age of 47 years) that underwent cementless total hip arthroplasty using third-generation ceramic-on-ceramic articulation were followed for 14-16 years. At final follow-up, there was no measurable ceramic wear and no periprosthetic osteolysis was identified. No ceramic fracture occurred during the follow-up. One hip was revised because of late infection. All prostheses were bone-ingrown. Two patients experienced a grinding sensation. However, no patient had squeak. The mean Harris hip score at the final evaluation was 89 points and the survival rate was 98.9%.

Are younger patients undergoing THA appropriately characterized as active?

BACKGROUND

Surgeons perform THA to address a variety of conditions in younger patients, including osteoarthritis (OA), osteonecrosis, inflammatory arthritis, and congenital deformities. Younger patients aged 50 years or younger have been characterized as active in the literature, but a direct relationship between age and activity level has not been well substantiated. Younger patients with OA may engage in higher activity levels; however, associated medical conditions in patients with other surgical indications may not support a generalization that age is a surrogate for activity level. We recently evaluated these issues in younger patients undergoing total knee arthroplasty (TKA) and noted that the majority would not be considered active. Given this observation, we considered whether younger patients undergoing THA are characterized by high activity levels, which is relevant to understanding the long-term risk of wear-related failures.

QUESTIONS/PURPOSES

(1) Do demographic features of younger patients undergoing THA support high activity expectations? (2) Do preoperative or postoperative functional activity measures support projections that younger patients are active after THA?

METHODS

We retrospectively compared demographic characteristics and functional activity profiles (as determined by preoperative and postoperative UCLA activity scores, Harris hip scores [HHS], and SF-12 and WOMAC physical function subscores) of 704 patients who had undergone THA and were aged younger than 50 years (822 hips) with those of 484 patients (516 hips) aged between 65 and 75 years, who had undergone THA, with a minimum followup at 1 year after surgery (range, 12-160 months).

RESULTS

Compared with patients aged 65 to 75 years, younger patients undergoing THA were more often men (51%, 95% confidence interval [CI], 48.8%-53.2% versus 40%, 95% CI, 37.1%-42.9% women; p < 0.01) or had undergone surgery for osteonecrosis (29% versus 4%; 95% CI, 2.8%-5.2%; p < 0.001). Postoperative HHS, SF-12, and WOMAC scores were not appreciably different between the two patient groups. Compared with older patients, younger patients with OA had higher preoperative (5.0 ± 2.5 versus 3.9 ± 2.0, p < 0.001) and postoperative UCLA activity scores (6.8 ± 2.1 versus 5.3 ± 1.9, p < 0.001). Younger patients with diagnoses other than OA had slightly higher mean postoperative UCLA activity scores than older patients (6.0 ± 2.3 versus 5.3 ± 1.9; p < 0.001). Two hundred fifty-nine of 704 younger patients undergoing THA (37%; 95% CI, 34.9%-39.1%) returned to impact activity compared with 75 of 484 older patients undergoing THA (15.5%; 95% CI, 13.3%-17.7%) (p < 0.001).

CONCLUSIONS

Younger patients with OA are likely to return to high levels of activity after surgery, which may impact long-term wear-related implant survivorship. High activity levels are less common among younger patients with diagnoses other than OA. Age is not the ideal surrogate for activity level in patients considering THA; instead, specific activity-level measures should be used when discussing patient expectations pertaining to postoperative activity levels after arthroplasty.

LEVEL OF EVIDENCE

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

Adverse reaction to metal debris in a patient with acetabular shell loosening 8 years after ceramic-on-metal total hip arthroplasty

A 41-year-old woman presented 8 years after a left total hip arthroplasty. She complained of progressive groin pain for several months. Radiographs demonstrated a hard-on-hard bearing surface combination and radiolucent lines surrounding the acetabular shell. Laboratory analysis revealed a mild leukocytosis, a normal erythrocyte sedimentation rate, and a mildly elevated C-reactive protein. Serum cobalt and chromium levels were markedly elevated. Aspiration of the hip joint was negative for infection. Magnetic resonance imaging failed to demonstrate a pseudotumor. Revision total hip arthroplasty was performed, and a ceramic-on-metal bearing surface combination was explanted. Significant intraoperative findings included dark gray synovial fluid, metal transfer onto the ceramic femoral head, and a grossly loose acetabular shell pivoting about a single well-fixed screw. The explanted components otherwise appeared normal macroscopically. Histologic analysis of the capsular tissue demonstrated aseptic lymphocyte-dominated vasculitis-associated lesion and inclusion bodies consistent with third-body wear. Revision arthroplasty to a ceramic-on-polyethylene bearing surface combination was performed with a good clinical result and laboratory normalization at 9-month follow-up.

Metasul vs Cerasul bearings: a prospective, randomized study at 9 years

The aims of our study were to compare metal-on-metal (Metasul) and ceramic-on-ceramic (Cerasul) bearings and to evaluate the clinical and radiographic results of these 2 different hard-on-hard bearings. We conducted a prospective, randomized study on a series of 250 cementless primary total hip arthroplasties. The prostheses were similar in all aspects except for the bearing surfaces: 50% of Metasul bearing and 50% of Cerasul bearing. All the patients were evaluated both clinically and radiographically. No patient was lost to follow-up. Clinical outcomes in both groups were similar. Considering aseptic loosening as the end point for failure, the 9-year survival rate was 100% for Cerasul and 98.4% for Metasul. Neither bearing outperformed the other both radiographically and clinically. The overall 9-year survival rate was 99.2% and 97.6% in the Cerasul and Metasul groups, respectively.

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.

High rate of ceramic sandwich liner fracture

BACKGROUND

Ceramic bearing surfaces for THA were introduced to reduce the risk of wear. However, owing to liner fracture in some of the early series and presumption that the fractures were the result of the modulus mismatch of the implant and the bone, a ceramic sandwich liner with lower structural rigidity was introduced. Fractures of these devices also were reported subsequently, although the incidence is unclear and it is unknown whether there are any risk factors associated with the fractures.

QUESTIONS/PURPOSES

We therefore determined the incidence of these fractures.

METHODS

We retrospectively reviewed 298 active patients in whom we implanted 353 ceramic-polyethylene sandwich liner acetabular components between November 1999 and February 2008. The mean age of the patients was 53.6 years (range, 17-84 years). The minimum followup was 6 months (mean, 41 months; range, 6-106 months). All patients were assessed clinically and radiographically.

RESULTS

Seven of the 353 (2%) ceramic sandwich liners fractured at a mean of 4.3 years (range, 1.3-7.6 years) after surgery without trauma. Neither patient-related factors nor radiographic position of the implants were risk factors for fracture.

CONCLUSIONS

Owing to the high rate of fractures of the sandwich ceramic polyethylene liners in our patients, we have discontinued use of this device.

LEVEL OF EVIDENCE

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

Long-term results of 32-mm alumina-on-alumina THA for avascular necrosis of the femoral head

Background

Ceramic bearings in total hip arthroplasty (THA) have been introduced in clinical practice to minimize the problem of polyethylene particle–induced osteolysis. The aim of the study is to report the results of 68 consecutive alumina-on-alumina THAs done in 61 patients for avascular necrosis (AVN) of the femoral head.

Materials and methods

In all implants a press-fit cup was used; it was combined with a 32-mm alumina head and with titanium-alloy stems. The mean age at surgery was 50 years. At an average follow-up of 13 years two hips have been revised, one for periprosthetic infection and one for excessive abduction of the cup.

Results

No revision for aseptic loosening is recorded; one anatomical cementless femoral stem had radiological evidence of definite aseptic loosening. No dislocations occurred, and no osteolysis was observed.

Conclusions

The results support the application of alumina-alumina THA for long-lasting replacements.

State of the art in hard-on-hard bearings: how did we get here and what have we achieved?

Total hip arthroplasty has shown excellent results in decreasing pain and improving function in patients with degenerative disease of the hip. Improvements in prosthetic materials, designs and implant fixation have now resulted in wear of the bearing surface being the limitation of this technology, and a number of hard-on-hard couples have been introduced to address this concern. The purpose of this article is to review the origins, development, survival rates and potential advantages and disadvantages of the following hard-on-hard bearings for total hip arthroplasty: metal-on-metal standard total hip arthroplasty; metal-on-metal hip resurfacing arthroplasty, ceramic-on-ceramic total hip arthroplasty; and ceramic-on-metal bearings. Improvements in the manufacturing of metal-on-metal bearings over the past 50 years have resulted in implants that provide low wear rates and allow for the use of large femoral heads. However, concerns remain regarding elevated serum metal ion levels, potential teratogenic effects and potentially devastating adverse local tissue reactions, whose incidence and pathogenesis remains unclear. Modern total hip resurfacing has shown excellent outcomes over 10 years in the hands of experienced surgeons. Current ceramic-on-ceramic bearings have demonstrated excellent survival with exceptionally low wear rates and virtually no local adverse effects. Concerns remain for insertional chipping, in vivo fracture and the variable incidence of squeaking. Contemporary ceramic-on-metal interfaces are in the early stages of clinical use, with little data reported to date. Hard-on-hard bearings for total hip arthroplasty have improved dramatically over the past 50 years. As bearing designs continue to improve with new and modified materials and improved manufacturing techniques, it is likely that the use of hard-on-hard bearings will continue to increase, especially in young and active patients.

Survival of hard-on-hard bearings in total hip arthroplasty: a systematic review

BACKGROUND

Improvements in prosthetic materials, designs, and implant fixation for THA have led to bearing surface wear being the limitation of this technology. Hard-on-hard bearings promise decreased wear rates and increased survival. However, there may be different survival rates based on bearing materials, manufacturing technologies, and femoral component designs. Additionally, survival rate variability may be based on study design.

QUESTIONS/PURPOSES

We determined survival rates and study levels of evidence and quality for the following bearings: stemmed metal-on-metal THA, metal-on-metal hip resurfacing, ceramic-on-ceramic THA, and ceramic-on-metal THA.

METHODS

We performed a systematic review of the peer-reviewed literature addressing THA hard-on-hard bearings. Quality for Level I and II studies was assessed.

RESULTS

The four Level I or II second-generation stemmed metal-on-metal THA studies reported between 96% and 100% mean survival at 38 to 60 months. The two Level I hip resurfacing studies reported 94% and 98% mean survival at 56 and 33 months. The four Level I studies of ceramic-on-ceramic THA reported survival from 100% at mean 51 months to 96% at 8 years.

CONCLUSIONS

While hard-on-hard bearing survival rates have generally been variable with earlier designs, contemporary implants have demonstrated survival of 95% or greater at followup of between 3 and 10 years. Some variability in survival may be due to differences in surgical technique, component positioning, and implant designs. As bearing designs continue to improve with modified materials and manufacturing techniques, use will increase, especially in young and active patients, though concerns remain about the increased reports of adverse events after metal-on-metal bearings.

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.

Incomplete seating of a metal-backed alumina liner in ceramic-on-ceramic total hip arthroplasty

Metal-backed modular ceramic bearing systems using a recessed alumina liner in a titanium sleeve were developed to decrease ceramic chipping or fracture due to femoral neck impingement after total hip arthroplasty (THA). However, malseating of the metal-backed ceramic liner has recently been described. The goal of this study was to assess the prevalence, etiology, and clinical relevance of this event. Between 2005 and 2008, 51 consecutive patients (61 hips) underwent THA with a metal-backed alumina liner housed in a titanium shell. The metal-backed ceramic liner was aligned, seated, and impacted into the shell, and satisfaction in terms of liner stability and seating was confirmed intraoperatively. Postoperative assessment of seating was assessed with standard radiographs. Liner seating was classified as well seated, suspicious, or malseated. Seven liners (11.5%) were found to be malseated and 4 (6.5%) were considered suspicious. Radiographically, there was a gap between the liner and the shell located inferomedially in 4 patients and superolaterally in 3 patients. Two liners subsequently seated at 1 and 3 months postoperatively, respectively. No dislodgement, failures, or adverse events were identified. There were no revision surgeries. The significant percentage of malseated liners were potentially attributed to poor exposure, bony/soft tissue interposition, and surgeon learning curve.

Survival of ceramic bearings in total hip replacement after high-energy trauma and periprosthetic acetabular fracture

Surgeons remain concerned that ceramic hip prostheses may fail catastrophically if either the head or the liner is fractured. We report two patients, each with a ceramic-on-ceramic total hip replacement who sustained high-energy trauma sufficient to cause a displaced periprosthetic acetabular fracture in whom the ceramic bearings survived intact. Simultaneous fixation of the acetabular fracture, revision of the cementless acetabular prosthesis and exchange of the ceramic bearings were performed successfully in both patients. Improved methods of manufacture of new types of alumina ceramic with a smaller grain size, and lower porosity, have produced much stronger bearings. Whether patients should be advised to restrict high-impact activities in order to protect these modern ceramic bearings from fracture remains controversial.

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.

Cementless total hip arthroplasty with alumina bearings in patients younger than fifty with femoral head osteonecrosis

BACKGROUND

There are conflicting reports with respect to the outcomes of total hip arthroplasties with ceramic bearings in young patients with osteonecrosis of the femoral head. We prospectively investigated the outcomes after cementless total hip arthroplasties with contemporary alumina bearings in patients with osteonecrosis of the femoral head in this age group.

METHODS

We prospectively followed sixty patients (seventy-one hips) with a mean age of 39.1 years for an average of 7.1 years. All procedures were performed at the same institution by one surgeon, and the results were evaluated serially. The clinical evaluations included use of the Harris hip score, and activities of daily living were evaluated with use of the criteria of Johnston et al.

RESULTS

The mean Harris hip score was 97.0 points at the time of final follow-up. Thirteen patients (fourteen hips, 20%) reported noise in the hip. Loosening or osteolysis was not observed in any hip, and no prosthesis had been revised. No hip had dislocated, and no ceramic fracture had occurred.

CONCLUSIONS

After a minimum of six years of follow-up, this cementless total hip arthroplasty with contemporary alumina bearings was found to be a promising procedure for young, active patients with osteonecrosis of the femoral head. However, we remain concerned about the long-term implications of the noise that was reported in these hips.

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.