Good stability but high periprosthetic bone mineral loss and late-occurring periprosthetic fractures with use of uncemented tapered femoral stems in patients with a femoral neck fracture

Increased Rates of Late Periprosthetic Fractures in Larger Hydroxyapatite-Coated Cementless Stems: Are Collared Stems a Better Alternative for Total Hip Arthroplasty?

BACKGROUND

Cementless hip stems are widely used for total hip arthroplasty (THA) and have demonstrated excellent survivorship. This study aimed to investigate the effects of stem size and calcar collars on rates of revision due to periprosthetic fracture.

METHODS

All primary THA procedures recorded by the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from September 1999 to December 2021 for a diagnosis of osteoarthritis using a single cementless hip stem with modern bearings were included. The primary outcome measure was revision due to periprosthetic fracture. Stems were divided into 2 groups for comparison, large (size 14 to 20) and small-medium (6 to 13). A subanalysis was performed for collared stems. A total of 59,518 primary THA procedures were included.

RESULTS

The cumulative percent revision for periprosthetic fracture was significantly higher for large stems compared to small-medium stems (hazard ratio [HR] = 1.57 [95% confidence interval {CI} 1.18, 2.09] P = .002). Furthermore, collared stems had significantly lower revision rates due to late periprosthetic fracture compared to collarless variants (2 week + HR = 4.55 [95% CI 3.23, 6.42], P < .001). Large collarless stems were found to have greater revision rates due to fracture compared to small-medium collarless stems (HR = 1.55 [95% CI 1.13, 2.12] P = .006), but no difference was found between collared groups (HR = 1.37 [95% CI 0.68, 2.78] P = .382).

CONCLUSION

Large cementless hip stems have a higher rate of revision due to periprosthetic fracture compared to small-medium stems. Using a collared stem reduces the rate of periprosthetic fracture.

Radiographic Evaluation and Changes in Bone Density of the Humeral Side after Reverse Total Shoulder Arthroplasty

After artificial joint surgery, bone density may decrease around the artificial joint; thus, postoperative bone density evaluation around the artificial joint is crucial. We investigated changes in bone mineral density and performed radiographic evaluation around the stem after reverse shoulder arthroplasty (RSA) surgery in 17 males (18 shoulders) and 19 females (19 shoulders), aged >65 years, with >1-year follow-up. In total, 20 and 17 cases involved massive rotator cuff tears and rotator cuff tear arthropathy, respectively. The Comprehensive Reverse Shoulder System (Standard Ingrowth) was used for all cases and cement was used in eight patients due to bone fragility. We examined lucent lines, loosening, bone resorption, and spot welds in non-cemented cases using plain radiography and postoperative bone density changes around the stem using dual-energy X-ray absorptiometry (DEXA). Lucent lines and bone resorption occurred in 5 (13.5%) and 19 (51.4%) shoulders, respectively. No loosening occurred. Compared to stem bone density at 2 weeks postoperatively, the decrease rate was the largest in the proximal medial humerus. One-year postoperative bone density was not related to sex, age, cement use, or preoperative diagnosis. Higher preoperative bone density was better maintained postoperatively. Furthermore, 1 year post RSA, spot welds were observed in approximately 48.2% of cases at the distal medial portion of the stem coating, and bone resorption occurred in the proximal medial humerus in 43.2% of cases. Therefore, postoperative bone density is related to preoperative bone density, suggesting the importance of maintaining high preoperative bone density.

Artificial Neural Networks Can Predict Early Failure of Cementless Total Hip Arthroplasty in Patients With Osteoporosis

BACKGROUND

Total hip arthroplasty (THA) done in the aging population is associated with osteoporosis-related complications. The altered bone density in osteoporotic patients is a risk factor for revision surgery. This study aimed to develop and validate machine learning (ML) models to predict revision surgery in patients with osteoporosis after primary noncemented THA.

METHODS

We retrospectively reviewed a consecutive series of 350 patients with osteoporosis (T-score less than or equal to -2.5) who underwent primary noncemented THA at a tertiary referral center. All patients had a minimum 2-year follow-up (range: 2.1 to 5.6). Four ML algorithms were developed to predict the probability of revision surgery, and these were assessed by discrimination, calibration, and decision curve analysis.

RESULTS

The overall incidence of revision surgery was 5.2% at a mean follow-up of 3.7 years after primary noncemented THA in osteoporotic patients. Revision THA was done because of periprosthetic fracture in nine patients (50%), aseptic loosening/subsidence in five patients (28%), periprosthetic joint infection in two patients (11%) and dislocation in two patients (11%). The strongest predictors for revision surgery in patients after primary noncemented THA were female sex, BMI (>35 kg/m2), age (>70 years), American Society of Anesthesiology score (≥3), and T-score. All four ML models demonstrated good model performance across discrimination (AUC range: 0.78 to 0.81), calibration, and decision curve analysis.

CONCLUSION

The ML models presented in this study demonstrated high accuracy for the prediction of revision surgery in osteoporotic patients after primary noncemented THA. The presented ML models have the potential to be used by orthopaedic surgeons for preoperative patient counseling and optimization to improve the outcomes of primary noncemented THA in osteoporotic patients.

Association of Sex With Risk of 2-Year Revision Among Patients Undergoing Total Hip Arthroplasty

IMPORTANCE

The worldwide population is aging and includes more female individuals than male individuals, with higher rates of total hip arthroplasty (THA) among female individuals. Although research on this topic has been limited to date, several studies are currently under way.

OBJECTIVES

To evaluate the association between sex and 2-year revision after THA.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from statewide databases in New York and California between October 1, 2015, and December 31, 2018. Patients 18 years or older with osteoarthritis who underwent THA and had sex recorded in the database were included in the analysis.

EXPOSURE

Total hip arthroplasty.

MAIN OUTCOMES AND MEASURES

The outcome of interest was the difference in early, all-cause revision surgery rates after primary THA between women and men. The association of sex with the revision rate was examined using Cox proportional hazards regression analysis.

RESULTS

Of 132 826 patients included in the study, 74 002 (55.7%) were women; the mean (SD) age was 65.9 (11.0) years, and the median follow-up time was 1.3 years (range, 0.0-3.0 years). The 2-year revision rate was 2.5% (95% CI, 2.4%-2.6%) among women and 2.1% (95% CI, 2.0%-2.2%) among men. After adjusting for demographic characteristics, comorbidities, and facility volume, a minimal clinically meaningful difference was observed in revision rates despite women having a higher risk of all-cause revision compared with men (hazard ratio, 1.16; 95% CI, 1.07-1.26; P < .001). The risk of revision was increased among women compared with men in the subgroup of patients who were younger than 55 years (hazard ratio, 1.47; 95% CI, 1.20-1.81; P < .001).

CONCLUSIONS AND RELEVANCE

In this cohort study, no clinically meaningful difference in all-cause revision rates after primary THA was found between men and women at 2-year follow-up. The modest difference in the risk of revision between men and women in a small subgroup of patients younger than 55 years suggests that the risk of revision in this population should be studied further.

Does radiopaque cement conceal periprosthetic bone loss around femoral stems?

BACKGROUND

Periprosthetic bone remodelling may increase fracture risk and deplete bone stock around hip implants. These changes are in part caused by implant design, advocating an early evaluation of bone remodelling properties of new implants. This can be done by repeated dual-energy x-ray absorptiometry (DXA) measurements. We know that radiopaque cement falsely elevates bone mineral density (BMD) in single measurements, however, its impact on repeated measurements, i.e. BMD changes is unexplored. We have therefore investigated whether the presence of radiopaque cement affect repeated BMD measurements.

METHODS

33 patients eligible for total hip replacement were randomly assigned to either radiopaque or radiolucent cement. BMD changes up to 12 months were measured by DXA, in addition to Harris Hip Score, plain radiographs and radiostereometric analysis (RSA).

RESULTS

Periprosthetic BMD declined during the first 3-6 months in all zones in both groups. The greatest reduction (14%) was seen in the proximal Gruen zones (1 and 7). We found a significant difference in Gruen zones 1 and 2, where the measured bone loss was higher in the radiolucent cement group.

CONCLUSIONS

The presence of radiopaque agents in bone cement may influence DXA measurements of bone remodelling.ClinicalTrials.gov identifier NCT00473421.

Low rates of all-cause revision in displaced subcapital femoral neck fractures treated with hip hemiarthroplasty - a retrospective review of 4516 patients from a single institute

Background

Femoral neck fracture (FNF) is among the commonest fractures affecting the geriatric population. Hemiarthroplasty (HA) is a standard treatment procedure and has been performed by hip surgeons for decades. Recently, primary total hip replacement has proved advantageous for the treatment of such fractures.

The aim of this study is to retrospectively review all causes of failure of all patients who underwent HA in our institute and reevaluated whether HA remains a favourable choice of treatment for patients with displaced FNFs.

Methods

A total of 4516 patients underwent HA at our centre from 1998 to 2017. The HA implants included unipolar and bipolar prostheses. Patients diagnosed with displaced FNF, underwent primary HA initially, required second revision procedures, and followed up for a minimum of 36 months were included in this study. Data were collected and comprehensively analysed.

Results

In 4516 cases, 99 patients underwent second surgeries. The revision rate was 2.19%. Reasons for failure were acetabular wear (n = 30, 30.3%), femoral stem subsidence (n = 24, 24.2%), periprosthetic fracture (n = 22, 22.2%), infection (n = 16, 16.2%), and recurrent dislocation (n = 7, 7.1%). The mean follow-up period was 78.1 months. The interval between failed HA and revision surgery was 22.8 months.

Conclusion

HA has a low revision rate and remains a favourable choice of treatment for patients with displaced FNFs.

Levels of evidence

Level III, Retrospective Cohort Study, Therapeutic Study.

Total hip arthroplasty in patients with osteoporosis

There is a high prevalence of osteoporosis in patients undergoing total hip arthroplasty. There are several clinically relevant questions related to the management of such cases: the effect of ageing; the initial osseointegration of implants, especially when cementless THA is used; the effect of medical osteoporosis treatment on bone-implant interface; the incidence of intraoperative and late periprosthetic fractures, and the long-term survival of both cemented and cementless total hip arthroplasty performed for proximal femoral fractures and hip osteoarthritis. A critical review of the literature is presented in an attempt to draw practical conclusions.

Bone Loss Following Cementless Hemiarthroplasty for the Treatment of Femoral Neck Fracture

BACKGROUND

With the advances in medicine, an increasing number of the ageing population are a public health concern in terms of age-related complications. Among them, displaced neck fractures often require surgical intervention or arthroplasty to achieve the mobilization of the elderly and good life quality. The aim of the study is to monitor the changes in bone mineral density (BMD) around the femoral stem and the effects on functional outcomes in patients treated with cementless hemiarthroplasty following femoral neck fracture.

MATERIALS AND METHODS

Seventy-one patients aged 70 years or older who were treated with cementless hemiarthroplasty for a displaced femoral neck fracture were prospectively followed for 2 years. The percent change in the periprosthetic BMD in each Gruen zone was compared to the baseline using dual-energy X-ray absorptiometry (DEXA). Demographic factors [age, body mass index (BMI), and sex] that could possibly influence BMD and the clinical outcome were evaluated.

RESULTS

Fifty-one patients were available for the final follow-up. The mean age was 76.5 (range 70-89) years. The mean BMI was 28.9 (range 22.7-37.2). The mean Harris hip score at the final follow-up was 84.3 (range 72-93). There was a significant decrease in BMD in all Gruen zones (p < 0.001), except in zone 3 (R3, p = 0.547). The reduction in BMD was highest in the calcar and the greater trochanter region. The femur diaphysis was relatively spared, with zone 3 showing no significant bone mineral loss. The age and BMI of the patients were not correlated with the postoperative change in BMD in any of the Gruen zones. The degree of reduction in bone density was not correlated with the clinical outcome.

CONCLUSIONS

Cementless hemiarthroplasty for the treatment of femoral neck fracture in elderly patients achieves a good clinical outcome despite significant bone loss around the femoral stem. The reduction in BMD is more pronounced in the metaphyseal region.

Effect of switching administration of alendronate after teriparatide for the prevention of BMD loss around the implant after total hip arthroplasty, 2-year follow-up: a randomized controlled trial

BACKGROUND

Stress shielding after total hip arthroplasty (THA) can induce bone mineral density (BMD) loss around the femoral implant. Several studies using drug have described methods to prevent BMD loss around implants following THA. Switching from teriparatide to alendronate was reported to increase lumbar BMD; on the other hands, it is unclear whether switching from teriparatide to alendronate is effective around the implant. The aim of this study is that changes in BMD is compared in patients switched from teriparatide to alendronate, in patients treated with alendronate alone, and in control patients without medication after total hip arthroplasty.

PATIENTS AND METHODS

Patients were randomized into three groups, those switched to alendronate after teriparatide (switch: n = 17), those receiving continuous alendronate (ALD: n = 15), and control untreated patients (control: n = 16) and followed up for 2 years after THA. Baseline periprosthetic BMD was measured by dual-energy X-ray absorptiometry (DEXA) 1 week after THA, followed by subsequent measurements at 1 and 2 years postoperatively. Lumbar BMD was also evaluated at preoperatively, 1 and 2 years postoperatively.

RESULTS

Two years after surgery, BMD (%) at zone 1 was significantly higher in the switch group than in the control group (P = 0.02). BMD (%) at zone 7 was significantly higher in the switch and ALD groups than in the control group (P = 0.01, P = 0.03). Lumbar BMD (%) anterior-posterior (AP) side was significantly higher in the switch group than in the ALD and control groups 2 years after surgery. On the other hand, lumbar BMD (%) lateral side was significantly higher in the switch and ALD groups than control group 2 years after surgery.

CONCLUSIONS

Switching therapy had a significant effect on BMD of the lumbar spine and zones 1 and 7 at 2 years postoperatively. At zone 1 in particular, it was found to be more effective than ALD alone.

TRIAL REGISTRATION

UMIN, registry number UMIN000016158. Registered 8 January 2015.

A Review of the Development and Application of Generic Preference-Based Instruments with the Older Population

Older people (aged 65 years and over) are the fastest growing age cohort in the majority of developed countries, and the proportion of individuals defined as the oldest old (aged 80 years and over) living with physical frailty and cognitive impairment is rising. These population changes put increasing pressure on health and aged care services, thus it is important to assess the cost effectiveness of interventions targeted for older people across health and aged care sectors to identify interventions with the strongest capacity to enhance older peoples' quality of life and provide value for money. Cost-utility analysis (CUA) is a form of economic evaluation that typically uses preference-based instruments to measure and value health-related quality of life for the calculation of quality-adjusted life-years (QALYS) to enable comparisons of the cost effectiveness of different interventions. A variety of generic preference-based instruments have been used to measure older people's quality of life, including the Adult Social Care Outcomes Toolkit (ASCOT); Health Utility Index Mark 2 (HUI2); Health Utility Index Mark 3 (HUI3); Short-Form-6 Dimensions (SF-6D); Assessment of Quality of Life-6 dimensions (AQoL-6D); Assessment of Quality of Life-8 dimensions (AQoL-8D); Quality of Wellbeing Scale-Self-Administered (QWB-SA); 15 Dimensions (15D); EuroQol-5 dimensions (EQ-5D); and an older person specific preference-based instrument-the Investigating Choice Experiments Capability Measure for older people (ICECAP-O). This article reviews the development and application of these instruments within the older population and discusses the issues surrounding their use with this population. Areas for further research relating to the development and application of generic preference-based instruments with populations of older people are also highlighted.

Fixation, sex, and age: highest risk of revision for uncemented stems in elderly women - data from 66,995 primary total hip arthroplasties in the Norwegian Arthroplasty Register

Background and purpose - There is no consensus on best method of fixation in hip arthroplasty. We investigated different modes of fixation in primary total hip arthroplasty (THA) and the influence of age and sex, to assess need for a differentiated approach.Patients and methods - The study was based on data from the Norwegian Arthroplasty Register in the period 2005-2017. Included were all-cemented, all-uncemented, reverse hybrid (uncemented stem and cemented cup), and hybrid (cemented stem and uncemented cup) THA designs that were commonly used, contemporary and well documented, using different causes of revision as endpoints.Results - From the included 66,995 primary THAs, 2,242 (3.3%) were revised. Compared with all-cemented THAs, all-uncemented had a higher risk of revision due to any cause (RR 1.4; CI 1.2-1.6), mainly due to an increased risk of periprosthetic fracture (RR 5.2; CI 3.2-8.5) and dislocation (RR 2.2; CI 1.5-3.0). Women had considerably higher risk of revision due to periprosthetic fracture after all-uncemented THA (RR 12; CI 6-25), compared with cemented. All-uncemented THAs in women of age 55-75 years (RR 1.3; CI 1.0-1.7) and over 75 years of age (RR 1.8; CI 1.2-2.7), and reverse hybrid THAs in women over the age of 75 (RR 1.5; CI 1.1-1.9) had higher risk of revision compared with cemented. Hybrid THAs (RR 1.0; CI 0.9-1.2) and reverse hybrid THAs (RR 1.0; CI 0.7-1.3) had similar risk of revision due to any cause as cemented THAs.Interpretation - Uncemented stems (all-uncemented and reverse hybrid THAs) had increased risk of revision in women over 55 years of age, mainly due to periprosthetic fracture and dislocation, and should probably not be used in THA in these patients.

A randomized controlled trial of cemented versus cementless arthroplasty in patients with a displaced femoral neck fracture

Aims

The aim of this study was to compare the functional and radiological outcomes in patients with a displaced fracture of the hip who were treated with a cemented or a cementless femoral stem.

Patients and Methods

A four-year follow-up of a randomized controlled study included 141 patients who underwent surgery for a displaced femoral neck fracture. Patients were randomized to receive either a cemented (n = 67) or a cementless (n = 74) stem at hemiarthroplasty (HA; n = 83) or total hip arthroplasty (THA; n = 58).

Results

Early differences in functional outcome, assessed using the Harris Hip Score, the Short Musculoskeletal Functional Assessment score and EuroQol-5D, with better results in cemented group, deteriorated over time and there were no statistically significant differences at 48 months. Two (3%) patients in the cemented group and five (6.8%) in the cementless group underwent further surgery for a periprosthetic fracture. This difference was statistically significant (p = 0.4). No patient underwent further surgery for instability or infection between one and four years postoperatively. The mortality and the radiological outcomes were similar in both groups.

Conclusion

Patients with a displaced femoral neck fracture treated with an arthroplasty using a cemented or cementless stem had good function and few complications up to four years postoperatively. However, due to the poor short-term functional outcomes in the cementless group, the findings do not support their routine use in the treatment of these elderly patients. Cite this article: Bone Joint J 2018;100-B:1087–93.

Less periprosthetic bone loss following the anterolateral approach to the hip compared with the direct lateral approach

Background and purpose - The loss of bone mineral in the proximal femur following hip arthroplasty may increase the fracture risk around uncemented stems. We hypothesized that the surgical approach to the hip might influence bone mineral changes around the femoral stem in patients with a femoral neck fracture (FNF). Patients and methods - This was a pre-specified subgroup analysis (n = 51) of an ongoing randomized trial (n = 120) in patients with FNF. Participants were allocated to an uncemented hemiarthroplasty inserted through a direct lateral (Hardinge) approach or an anterolateral (modified Watson-Jones) approach. The 51 patients (mean age 83 (70-90) years, 33 women) were measured by dual-energy X-ray absorptiometry (DXA) to assess changes in periprosthetic bone mineral density (BMD). Results - The mean change in total BMD differed between groups at 12 months in favor of the anterolateral group (4.8%, 95% CI 0.0-9.6; p = 0.05). DXA at 3 months displayed BMD loss in the proximal Gruen zones in the lateral group compared with the anterolateral group. Zone 1 (-5.0% vs. 2.7%), zone 2 (-4.3% vs. 4.1%), zone 6 (-6.5% vs. 0.0%) and zone 7 (-11% vs. -2.4%, all p < 0.05). Interpretation - DXA measurements in this study indicate that surgical approach to the hip influences periprosthetic BMD. Clinical implications remain uncertain. Our conclusions should be interpreted with caution as we did not perform adjustments for multiple tests, possibly leading to inflation of false-positive findings.

More complications with uncemented than cemented femoral stems in total hip replacement for displaced femoral neck fractures in the elderly

Background and purpose - Total hip replacement (THR) is the preferred method for the active and lucid elderly patient with a displaced femoral neck fracture (FNF). Controversy still exists regarding the use of cemented or uncemented stems in these patients. We compared the effectiveness and safety between a modern cemented, and a modern uncemented hydroxyapatite-coated femoral stem in patients 65-79 years of age who were treated with THR for displaced FNF. Patients and methods - In a single-center, single-blinded randomized controlled trial, we included 69 patients, mean age 75 (65-79) and with a displaced FNF (Garden III-IV). 35 patients were randomized to a cemented THR and 34 to a reverse-hybrid THR with an uncemented stem. Primary endpoints were: prevalence of all hip-related complications and health-related quality of life, evaluated with EuroQol-5D (EQ-5D) index up to 2 years after surgery. Secondary outcomes included: overall mortality, general medical complications, and hip function. The patients were followed up at 3, 12, and 24 months. Results - According to the calculation of sample size, 140 patients would be required for the primary endpoints, but the study was stopped when only half of the sample size was included (n = 69). An interim analysis at that time showed that the total number of early hip-related complications was substantially higher in the uncemented group, 9 (among them, 3 dislocations and 4 periprosthetic fractures) as compared to 1 in the cemented group. The mortality and functional outcome scores were similar in the 2 groups. Interpretation - We do not recommend uncemented femoral stems for the treatment of elderly patients with displaced FNFs.

Periprosthetic femoral fractures and trying to avoid them: what is the contribution of femoral component design to the increased risk of periprosthetic femoral fracture?

AIMS

Periprosthetic femoral fractures (PFF) following total hip arthroplasty (THA) are devastating complications that are associated with functional limitations and increased overall mortality. Although cementless implants have been associated with an increased risk of PFF, the precise contribution of implant geometry and design on the risk of both intra-operative and post-operative PFF remains poorly investigated. A systematic review was performed to aggregate all of the PFF literature with specific attention to the femoral implant used.

PATIENTS AND METHODS

A systematic search strategy of several journal databases and recent proceedings from the American Academy of Orthopaedic Surgeons was performed. Clinical articles were included for analysis if sufficient implant description was provided. All articles were reviewed by two reviewers. A review of fundamental investigations of implant load-to-failure was performed, with the intent of identifying similar conclusions from the clinical and fundamental literature.

RESULTS

In total 596 articles were initially identified, with 34 being eligible for analysis. Aggregate analysis of 1691 PFFs in 342 719 primary THAs revealed a significantly higher number of PFFs with cementless femoral implants (p < 0.001). Single-wedge and double-wedge (fit-and-fill) femoral implants were associated with a threefold increase in PFF rates (p < 0.001) compared with anatomical, fully coated and tapered/rounded stems. Within cemented stems, loaded-taper (Exeter) stems were associated with more PFFs than composite-beam (Charnley) stems (p = 0.004). Review of the fundamental literature revealed very few studies comparing cementless component designs.

CONCLUSION

Very few studies within the PFF literature provide detailed implant information. Cementless implants, specifically those of single-wedge and double-wedge, have the highest PFF rates in the literature, with most investigations recommending against their use in older patients with osteoporotic bone. This review illustrates the need for registries and future PFF studies to record implant name and information for future analysis. Furthermore, future biomechanical investigations comparing modern implants are needed to clarify the precise contribution of implant design to PFF risk. Cite this article: Bone Joint J 2017;99-B(1 Supple A):50-9.

Incidence and Risk Period of Periprosthetic Femoral Fracture After Cementless Bipolar Hemiarthroplasty in Elderly Patients

BACKGROUND

The purpose of this study was to investigate the periprosthetic femoral fracture (PFF) after cementless bipolar hemiarthroplasty incidence, noting fracture types and the results of treatment in elderly patients.

METHODS

We retrospectively reviewed 1563 elderly patients (1177 women and 386 men) who underwent cementless bipolar hemiarthroplasty for femoral neck fracture (1061 patients) or intertrochanteric fracture (502 patients). The type of fracture was classified according to the Vancouver classification. The average age was 79.6 years (range, 65-103 years). Clinical and radiologic evaluations were performed and Kaplan-Meier survivorship was analyzed.

RESULTS

Thirty-seven PFFs (2.4%) occurred during a mean follow-up of 44.4 months. Two-thirds of PFFs (67%) occurred within 1 year. Most PFFs (22/27), which occurred within 2 years, were Vancouver type B fractures. After that, type A fractures were predominant (7/9). Based on Kaplan-Meier survivorship with PFF as the end point, the incidence rate was 1.7% (95% confidence interval [CI] = 1.6%-1.8%) at 12 months, 2.2% (95% CI = 2.1%-2.3%) at 36 months, and 3.8 % (95% CI = 3.6%-4.0%) at 144 months postoperatively.

CONCLUSION

After cementless bipolar hemiarthroplasty in elderly patients, a caution should be paid to prevent PFF particularly during 1-year postoperatively.

Cemented versus uncemented arthroplasty in patients with a displaced fracture of the femoral neck

The aim of this randomised controlled study was to compare functional and radiological outcomes between modern cemented and uncemented hydroxyapatite coated stems after one year in patients treated surgically for a fracture of the femoral neck. A total of 141 patients aged > 65 years were included. Patients were randomised to be treated with a cemented Exeter stem or an uncemented Bimetric stem. The patients were reviewed at four and 12 months.

The cemented group performed better than the uncemented group for the Harris hip score (78 vs 70.7, p = 0.004) at four months and for the Short Musculoskeletal Function Assesment Questionnaire dysfunction score at four (29.8 vs 39.2, p = 0.007) and 12 months (22.3 vs 34.9, p = 0.001). The mean EQ-5D index score was better in the cemented group at four (0.68 vs 0.53, p = 0.001) and 12 months (0.75 vs 0.58, p = < 0.001) follow-up. There were nine intra-operative fractures in the uncemented group and none in the cemented group.

In conclusion, our data do not support the use of an uncemented hydroxyapatite coated stem for the treatment of displaced fractures of the femoral neck in the elderly.

Cite this article: Bone Joint J 2015;97-B:1475–80.

Revision total hip arthroplasty using cemented collarless double-taper femoral components at a mean follow-up of 13 years (8 to 20): an update

The outcome of 219 revision total hip arthroplasties (THAs) in 98 male and 121 female patients, using 137 long length and 82 standard length cemented collarless double-taper femoral stems in 211 patients, with a mean age of 72 years (30 to 90) and mean follow-up of six years (two to 18) have been described previously. We have extended the follow-up to a mean of 13 years (8 to 20) in this cohort of patients in which the pre-operative bone deficiency Paprosky grading was IIIA or worse in 79% and 73% of femurs with long and standard stems, respectively. For the long stem revision group, survival to re-revision for aseptic loosening at 14 years was 97% (95% confidence interval (CI) 91 to 100) and in patients aged > 70 years, survival was 100%. Two patients (two revisions) were lost to follow-up and 86 patients with 88 revisions had died. Worst-case analysis for survival to re-revision for aseptic loosening at 14 years was 95% (95% CI 89 to 100) and 99% (95% CI 96 to 100) for patients aged > 70 years. One additional long stem was classified as loose radiographically but not revised. For the standard stem revision group, survival to re-revision for aseptic loosening at 14 years was 91% (95% CI 83 to 99). No patients were lost to follow-up and 49 patients with 51 hips had died. No additional stems were classified as loose radiographically. Femoral revision using a cemented collarless double-taper stem, particularly with a long length stem, and in patients aged > 70 years, continues to yield excellent results up to 20 years post-operatively, including in hips with considerable femoral metaphyseal bone loss.

No effect of risedronate on femoral periprosthetic bone loss following total hip arthroplasty. A 4-year follow-up of 61 patients in a double-blind, randomized placebo-controlled trial

BACKGROUND AND PURPOSE

We have previously shown that during the first 2 years after total hip arthroplasty (THA), periprosthetic bone resorption can be prevented by 6 months of risedronate therapy. This follow-up study investigated this effect at 4 years.

PATIENTS AND METHODS

A single-center, double-blind, randomized placebo-controlled trial was carried out from 2006 to 2010 in 73 patients with osteoarthritis of the hip who were scheduled to undergo THA. The patients were randomly assigned to receive either 35 mg risedronate or placebo orally, once a week, for 6 months postoperatively. The primary outcome was the percentage change in bone mineral density (BMD) in Gruen zones 1 and 7 in the proximal part of the femur at follow-up. Secondary outcomes included migration of the femoral stem and clinical outcome scores.

RESULTS

61 of the 73 patients participated in this 4-year (3.9- to 4.1-year) follow-up study. BMD was similar in the risedronate group (n = 30) and the placebo group (n = 31). The mean difference was -1.8% in zone 1 and 0.5% in zone 7. Migration of the femoral stem, the clinical outcome, and the frequency of adverse events were similar in the 2 groups.

INTERPRETATION

Although risedronate prevents periprosthetic bone loss postoperatively, a decrease in periprosthetic BMD accelerates when therapy is discontinued, and no effect is seen at 4 years. We do not recommend the use of risedronate following THA for osteoarthritis of the hip.

Analysis of migration of the Nanos® short-stem hip implant within two years after surgery

PURPOSE

Short-stem implants provide a bone-preserving alternative in total hip arthroplasty. However, some evidence exists that the smaller implant-bone contact surface may compromise primary stability and impair osseo-integration. The purpose of this study was to analyse the migration characteristics of the Nanos® short stem over two years by means of model-based roentgen stereophotogrammetric analysis (MBRSA).

METHODS

Eighteen patients aged 53.6 ± 7.2 years were included. After being treated with a Nanos implant, 14 patients were followed-up radiologically at three, six, 12 and 24 months by means of MBRSA. Early implant migration was calculated. Clinical data have been assessed in addition.

RESULTS

Highest translational migration was observed with a mean value of -0.22 ± 0.39 mm along the proximo-distal axis after three months and highest rotational migration with 0.8 ± 3.2° also around the y-axis after two years. The resulting total migration was 0.46 ± 0.31 mm, with the largest proportion occurring within three months after surgery (0.40 ± 0.34 mm).

CONCLUSION

The Nanos short-stem hip implant shows only a slight initial migration within three months after implantation, followed by secondary stabilisation. These results suggest both good primary stability and osseo-integration, suggesting a low risk of aseptic loosening.