Factors affecting dislocation after bipolar hemiarthroplasty in patients with femoral neck fracture

Dual mobility cup in hip fracture: Indications and clinical results compared with bipolar hip arthroplasty

INTRODUCTION

The choice between hemiarthroplasty (HA) and total hip arthroplasty (THA) for displaced femoral neck fractures remains debated. There is increasing use in dual mobility cup total hip arthroplasty (DMC-THA) to prevent dislocations in these high-risk patients. Aim of this study is to retrospectively analyze patients treated in a single Center for femoral neck fracture comparing HA and DMC-THA in terms of: functional outcome, rate of complications and mortality.

MATERIAL AND METHODS

Between 2020 and 2022, 162 patients were included, 39 male and 123 female, with a mean age of 76 years old. HA were implanted in 82 cases and DMC-THA in 80 cases. INCLUSION CRITERIA WERE: age < 85 years old, American Society of Anesthesiologists (ASA) score below 3, minimum follow-up of 6 months. Overall, 124/162 of patients (77%) were surgically treated within 48 h from admission.

RESULTS

The mean age for DMC-THA group was 74 years old and 78 years old for HA group. The overall mean surgical time was significantly higher in the DMC-THA group (P < 0.001). Mean hemoglobin (Hb) loss was 1.64 g/dl in the HA group and 1.72 g/dl in the DMC-THA group with no differences between the two groups (P = 0.573). There is no difference in survival of patients between the two groups (P = 0.7704). In the HA group, the mean one-month post-operative VAS score was 2.1, while in the DMC-THA group was 0.9. The Harris hip score was significantly better in DMC-THA group (P = 0.035) Dislocation never occured in the overall series. Infection occurred only in one patient with DMC-THA and was treated with debridement. Periprosthetic fracture occurred in 2 cases of DMC-THA both within 1 month from the first surgery; one was treated with revision femoral stem and the second one with fixation.

CONCLUSIONS

DMC-THA offer better functional results than HA in elderly patients with femur neck fractures. The mean surgical time was longer in DMC-THA but this did not influence blood loss, time of discharge or one-year mortality. In our series dislocation never occurred in both groups.

Complication rates after direct anterior vs posterior approach for hip hemiarthroplasty in elderly individuals with femoral neck fractures

BACKGROUND

Dislocation rates after hemiarthroplasty reportedly vary from 1% to 17%. This serious complication is associated with increased morbidity and mortality rates. Approaches to this surgery are still debated, with no consensus regarding the superiority of any single approach.

AIM

To compare early postoperative complications after implementing the direct anterior and posterior approaches (PL) for hip hemiarthroplasty after femoral neck fractures.

METHODS

This is a comparative, retrospective, single-center cohort study conducted at a university hospital. Between March 2008 and December 2018, 273 patients (a total of 280 hips) underwent bipolar hemiarthroplasties (n = 280) for displaced femoral neck fractures using either the PL (n = 171) or the minimally invasive direct anterior approach (DAA) (n = 109). The choice of approach was related to the surgeons' practices; the implant types were similar and unrelated to the approach. Dislocation rates and other complications were reviewed after a minimum follow-up of 6 mo.

RESULTS

Both treatment groups had similarly aged patients (mean age: 82 years), sex ratios, patient body mass indexes, and patient comorbidities. Surgical data (surgery delay time, operative time, and blood loss volume) did not differ significantly between the groups. The 30 d mortality rate was higher in the PL group (9.9%) than in the DAA group (3.7%), but the difference was not statistically significant (P = 0.052). Among the one-month survivors, a significantly higher rate of dislocation was observed in the PL group (14/154; 9.1%) than in the DAA group (0/105; 0%) (P = 0.002). Of the 14 patients with dislocation, 8 underwent revision surgery for recurrent instability (posterior group), and one of them had 2 additional procedures due to a deep infection. The rate of other complications (e.g., perioperative and early postoperative periprosthetic fractures and infection-related complications) did not differ significantly between the groups.

CONCLUSION

These findings suggest that the DAA to bipolar hemiarthroplasty for patients with femoral neck fractures is associated with a lower dislocation rate (< 1%) than the PL.

Long-term risk of reoperation after modular hemiarthroplasty : Any differences between uni- or bipolar design?

BACKGROUND

It is unclear whether unipolar (UHA) or bipolar (BHA) hemiarthroplasty should be the preferred treatment of femoral neck fracture (FNF).

AIM

We investigated the reoperation rate at 13 years post-fracture after BHA and UHA as treatment of FNF, including a subgroup analysis of individuals who survived 5 years or more, and described the reasons for reoperation after BHA and UHA respectively.

METHODS

In an observational cohort study on prospectively collected national register data, 16,216 BHA and 22,186 UHA were available for matching. A propensity score for treatment with bipolar HA was estimated using logistic regression. Matching was done using the 1:1 nearest neighbor matching without replacement. Of the 16,216 BHA patients, 12,280 were matched to a UHA control. A subgroup analysis based on the matched sample excluded individuals who died within 5 years and comprised 3,637 individuals with BHA and 3,537 with UHA. Kaplan-Meier survival analysis was used.

RESULTS

In the Kaplan-Meier analysis, 92% of the BHA group was free from reoperation at 13 years (95% CI 0.91-0.93), compared to 92% in the UHA group (CI 0.89-0.94). BHA was associated with more reoperations until 3 years. Reoperation due to infection was most common after BHA, n = 212 (1.7%) compared to n = 141 (1.1%) after UHA. Dislocation led to reoperation in 192 of the BHA cases (1.6%) and in 157 of the UHA cases (1.3%). Acetabular erosion/pain occurred in 0.1% and 0.4%. Amongst those surviving ≥ 5 years, 93% of the BHA group was free from reoperation (CI 0.92-0.94) at 13 years, 92% after UHA (CI 0.90-0.94). BHA had more reoperations during the 1st year only. The causes for reoperations showed similar rates except for acetabular erosion/pain. Here the BHA group had 2 cases (0.1%), the UHA had 39 (1.1%).

CONCLUSION

With a modular hemiarthroplasty relatively few patients need a reoperation. During the first years, there is a higher reoperation rate after BHA compared to UHA. Thereafter, no differences are seen. In patients who survive ≥ 5 years after the fracture there are more reoperations due to acetabular erosion after UHA, but crude numbers are extremely low, and the total reoperation rate is not affected.

Acetabular Morphology Predicts the Risk of Dislocation Following Hemiarthroplasty for Femoral Neck Fractures in the Elderly

BACKGROUND

Hip hemiarthroplasty dislocation is a devastating complication. Among other preoperative risk factors, acetabular morphology has been rarely studied. The purpose of the study was to evaluate the influence of preoperative native acetabular morphology on hemiarthroplasty dislocation.

METHODS

We retrospectively reviewed 867 patients who underwent hip hemiarthroplasty for femoral neck fracture between January 1, 2014 and January 1, 2019. The 380 included patients were treated with an anterior-based muscle-sparing approach. The central-edge angle (CEA) and acetabular depth-to-width ratio (ADWR) of the fractured hip were measured preoperatively on the anteroposterior pelvic view. Receiver operating characteristic curves were performed to analyze the optimal cutoff for CEA and ADWR. Hemiarthroplasty dislocation occurred in 18 patients (4.7%), and the remaining 362 patients were used as the control group.

RESULTS

No significant differences in terms of sex, age, dementia, neuromuscular disease, and body mass index were found between the 2 groups. The 18 patients who had a hip dislocation had significantly smaller mean CEA than the control group (P = .0001) (mean 36.1 ± 7.5° and 43.2 ± 5.6°, respectively) as well as ADWR (mean 34 ± 6 versus 37 ± 4, respectively) (P = .001). Using the receiver operating characteristic analysis, we report significant cutoffs of 38.5° for CEA (P = .0001) and 34.5 for the ADWR (P = .017).

CONCLUSION

Higher rates of hemiarthroplasty dislocation were observed in patients who had a preoperative CEA of less than 38.5° and an ADWR of less than 34.5. Patients who have preoperative acetabular morphological risk factors for dislocation might be better candidates for a total hip arthroplasty.

A systematic review and meta-analysis of cemented and uncemented bipolar hemiarthroplasty for the treatment of femoral neck fractures in elderly patients over 60 years old

Background

Currently, whether bone cement can be applied in bipolar hemiarthroplasty to treat femoral neck fractures (FNFs) in elderly patients is controversial. The aim of this systematic review and meta-analysis was to compare the effectiveness and safety of cemented bipolar hemiarthroplasty (CBH) versus uncemented bipolar hemiarthroplasty (UCBH) in the treatment of FNFs among elderly patients over 60 years old.

Materials and methods

The Pubmed, Web of science, Cochrane Library and EMBASE databases were searched comprehensively for relevant articles from their inception to May 2022. Studies about comparing outcomes between CBH and UCBH for FNFs in elderly patients aged more than 60 years were included. Outcomes including operation time, intra-operative blood loss, length of hospital stay, wound infections, residual pain, revisions, re-operations, complications related to prosthesis, general complications, and mortality. The Review Manager 5.3 software provided by the Cochrane Collaboration Network was used to perform the meta-analysis of comparable data.

Results

A total of 6 randomized controlled trials (RCTs) and 9 observational studies were included in this analysis, with 33,118 patients (33,127 hips). Results of the meta-analysis indicated that the operation time [WMD = 13.01 min, 95% CI (10.79, 15.23)], intra-operative blood loss [WMD = 80.57 ml, 95% CI (61.14, 99.99)], incidence of heterotrophic ossification [OR = 2.07, 95% CI (1,14, 3.78)], were increased in the CBH group but the incidence of intra-operative fractures [OR = 0.24, 95% CI (0.07, 0.86)], periprosthetic fractures [OR = 0.24, 95% CI (0.18, 0.31)], aseptic loosening of prosthesis [OR = 0.20, 95% CI (0.09, 0.44)], wound infections [OR = 0.80, 95% CI (0.68, 0.95)] and re-operation rates [OR = 0.61, 95% CI (0.54, 0.68)] were lower in the CBH group by comparison with the UCHB group. However, there were no significant differences in residual pain, length of hospital stay, prosthetic dislocation, prosthetic subsidence (> 5 mm), acetabulum erosion, revisions, pulmonary infections, pulmonary embolisms, urinary tract infections, deep venous thromboses, decubitus, cardiovascular accidents (arrhythmia/myocardial infarction), and respiratory failure between the two groups. In terms of mortality, perioperative mortality (within 72 h) [OR = 2.39, 95% CI (1.71, 3.32)] and 1-week mortality postoperatively [OR = 1.22, 95% CI (1.05, 1.41)] in CBH group were higher than those in UCBH group, but there were no significant differences in mortality at 1 month, 3 months, 1 year, and 2 years postoperatively between CBH group and UCBH group.

Conclusion

This meta-analysis found that elderly patients over 60 years old with FNFs who underwent CBH had longer operation time, higher incidence of heterotrophic ossification, intra-operative blood loss, and mortality within 72 h of operation and at 1-week postoperatively, but lower incidence of periprosthetic fractures, aseptic loosening of prosthesis, intra-operative fractures, wound infections and re-operations. Other outcomes were not significantly different between the two groups.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42021274253.

Effect of hip hemiarthroplasty dislocation on mortality after hip fracture surgery

INTRODUCTION

Hip arthroplasty is the treatment of choice for displaced femoral neck fractures among the older population. The hip prosthesis dislocation is one of the most pointed potential complications after hip arthroplasty, but there is a lack of updated information on the effect of dislocation on the survival of older hip fracture patients so treated by hip hemiarthroplasty. We aim to evaluate the standalone effect of hip prosthesis dislocation after hip fracture hemiarthroplasty on patients' survival outcomes.

MATERIALS AND METHODS

We conducted a retrospective multicenter study, including 6631 femoral neck fracture patients over 65 surgically treated by hemiarthroplasty. We made follow-up cut-offs 30-days, 6 weeks, 90-days, and one year after hospital discharge determining hip dislocation rate and patients' survival.

RESULTS

The women population represented 78.7%, and the mean age of the population was 85.2 ± 6.7 years. Hip prosthesis dislocation incidence was 1.9% in the first 90-days after discharge, representing 91.54% of primary dislocations yearly noted. We reported statistically significant increased mortality rates of patients presenting at least one hip prosthesis dislocation event (from 16.0% to 24.6% at 90-day after discharge, and 29.5% to 44.7% at one year), and also significantly decreasing patient survival function at 90-day (P = .016) and one-year follow-up (P < .001). The recurrent dislocation events (26.15%) showed even higher mortality rates (up to 60.6%, p < .001). The multivariate Cox regression model determined that prosthesis dislocation was the only significant variable (P = .035) affecting patient survival, increasing the risk of dying before one year of follow-up by 2.7 times.

DISCUSSION

Our study stands for the standalone hip prosthesis dislocation entailing a higher risk of death after hip fracture hemiarthroplasty in the older population.

Effect of hip hemiarthroplasty dislocation on mortality after hip fracture surgery

INTRODUCTION

Hip arthroplasty is the treatment of choice for displaced femoral neck fractures among the older population. The hip prosthesis dislocation is one of the most pointed potential complications after hip arthroplasty, but there is a lack of updated information on the effect of dislocation on the survival of older hip fracture patients so treated by hip hemiarthroplasty. We aim to evaluate the standalone effect of hip prosthesis dislocation after hip fracture hemiarthroplasty on patients' survival outcomes.

MATERIALS AND METHODS

We conducted a retrospective multicenter study, including 6631 femoral neck fracture patients over 65 surgically treated by hemiarthroplasty. We made follow-up cut-offs 30-days, 6 weeks, 90-days, and one year after hospital discharge determining hip dislocation rate and patients' survival.

RESULTS

The women population represented 78.7%, and the mean age of the population was 85.2±6.7 years. Hip prosthesis dislocation incidence was 1.9% in the first 90-days after discharge, representing 91.54% of primary dislocations yearly noted. We reported statistically significant increased mortality rates of patients presenting at least one hip prosthesis dislocation event (from 16.0% to 24.6% at 90-day after discharge, and 29.5% to 44.7% at one year), and also significantly decreasing patient survival function at 90-day (p=0.016) and one-year follow-up (p<0.001). The recurrent dislocation events (26.15%) showed even higher mortality rates (up to 60.6%, p<0.001). The multivariate Cox regression model determined that prosthesis dislocation was the only significant variable (p=0.035) affecting patient survival, increasing the risk of dying before one year of follow-up by 2.7 times.

DISCUSSION

Our study stands for the standalone hip prosthesis dislocation entailing a higher risk of death after hip fracture hemiarthroplasty in the older population.

The impact of increasing femoral offset and stem anteversion on postoperative dislocation in bipolar hemiarthroplasty

BACKGROUND

Femoral offset and anteversion have been reported to affect the incidence of dislocation following bipolar hemiarthroplasty, although the magnitudes of contributions of the femoral offset and stem anteversion on dislocation, both singly and in combination is not fully understood.

METHODS

Using the CT data of 61 patients (61 hips), including 30 male and 31 female who underwent bipolar hemiarthroplasty, three-dimensional dynamic motion analysis was performed using a modular implant that enabled adjustment of femoral offset and stem anteversion independently. The pattern of impingement and relationship between femoral offset/stem anteversion and range of motion were evaluated using the software.

FINDINGS

We found that a higher femoral offset and stem anteversion correlate with a greater range of motion of flexion and internal rotation. Furthermore, an increased femoral offset has a great effect on increasing range of motion of flexion than stem anteversion, and increased both femoral offset and stem anteversion have fewer effect on the flexion, whereas increasing stem anteversion has a great impact on internal rotation than offset, especially in the case with lower femoral anteversion. However, a higher stem anteversion decrease the range of motion of external rotation, whereas a higher femoral offset leads to an increased range of motion of external rotation.

INTERPRETATION

We demonstrated that both a higher femoral offset and stem anteversion substantially affected the range of motion in flexion, internal rotation and external rotation. However, these are not independent, but rather mutually confounding, the surgeons should consider retaining femoral/anterior offset in bipolar hemiarthroplasty.

Anatomical Parameters Associated with the Shortening Decision in Crowe Type 4 Dysplastic Hip Osteoarthritis: A Case-Control Study

Background

Muscle and bone morphometry may be potent indicators for predicting femoral subtrochanteric shortening osteotomy (FSSO). We aimed to investigate muscular and bony factors that may be predictive of FSSO.

Methods

Patients with unilateral Crowe type 4 developmental dysplasia of the hip (DDH) who underwent unilateral total hip arthroplasty (THA) without (Group 1, 31 patients) and with FSSO (Group 2, 39 patients) were included. Sixty healthy hips (Group 3) were selected as the control group. Several muscular and bony parameters were measured on the operative (O) and non-operative (NO) hips on radiographs and computed tomography (CT) images.

Results

The mean NO gluteus medius cross-sectional area (CSA) index (NO-GMed CI), NO tensor fasia lata (TFL) CI, NO iliopsoas (IP) CI, and NO gluteus maximus (GMax) CI for the control group were lower than those for both Crowe type IV DDH with and without FSSO. The mean NO gluteus minimus CI (NO-GMin CI) for the control group were higher than those for both Crowe type IV DDH with and without FSSO. There was significant difference between Groups 1 and 2 regarding axial position of neo-acetabulum (APNA) (- 0.03 ± 8.5 vs. 5.27 ± 6.33, p = 0.004), coronal position of neo-acetabulum (CPNA) (33.39 ± 10.65 vs. 53.70 ± 12.27, p = 0.000), operative leg length discrepancy (O-LLD) (14.18 ± 15.14 vs. 24.44 ± 15.80, p = 0.001), O-gluteus minimus (GMin) length (155.34 ± 157.73 vs. 106.79 ± 20, p =  < 0.01), and O-GMin CI (57.28 ± 58.59 vs. 29.95 ± 12.13, p =  < 0.01). The cutoff values determined by the receiving operating curve analyses were as follows: 13.7 mm, 2.5 mm, and 41.4 mm for O-LLD, APNA, and CPNA, respectively.

Conclusion

FSSO is associated with APNA, CPNA, O-LLD, O-GMin length, and O-GMin CI. By using cutoff values of APNA, CPNA, and O-LLD, predicting FSSO preoperatively is possible. Owing to these parameters, it may be possible to lower the technically demanding level of surgery.

Acetabular morphological variation in Asian patients with femoral neck fracture: A three-dimensional CT-based study

AIMS

The acetabular morphology varies greatly among individuals, and hypoplasia is more common in Asia than in Europe. Dislocation after bipolar hip arthroplasty (BHA) for femoral neck fracture occurs at a constant rate, and is affected by the acetabular morphology. This study aimed to clarify individual differences in the acetabula of Asian patients with displaced femoral neck fractures.

PATIENTS AND METHODS

Fifty patients with displaced femoral neck fractures were assessed (50 fractured hips, 50 non-fractured hips). On CT corrected by the anterior pelvic plane, the 100 hips were assessed regarding acetabular coverage (six parameters), acetabular depth (two parameters), and acetabular opening angle (four parameters). Additional parameters related to the fracture and sex were examined. The percentile of each parameter was shown for all hips.

RESULTS

There was no patient with hip dysplasia defined as superior acetabular sector angle (SASA) less than 110° Compared with men, women had a significantly smaller anterior acetabular sector angle (AASA) (p = 0.016), and significantly larger acetabular inclination angle (p = 0.006) and acetabular index angle (p = 0.034). In the group with a normal SASA, seven hips (7.3%) had an anterior wall defect (AASA<50°) and five hips (5.2%) had a posterior wall defect (posterior acetabular sector angle<90°).

CONCLUSION

Older adults with femoral neck fractures can have anterior wall and posterior wall defects, even if their SASA is normal. Hidden acetabular dysplasia may be related to post-BHA dislocation. So, our results suggest that is important to accurately evaluate the acetabulum of patients with femoral neck fracture before surgery.

Factors associated with dislocation after bipolar hemiarthroplasty through an (antero-)lateral approach in elderly patients with a femoral neck fracture: a retrospective cohort study with a nested case-control subanalysis of radiographic parameters

Introduction

Dislocations of hip hemiarthroplasty (HHA) are serious complications. The aim of the study was to identify clinical aspects and radiographic parameters of the hip that put patients at risk for dislocation after HHA for femoral neck fractures.

Methods

This retrospective analysis included elderly patients with a femoral neck fracture treated with a HHA. A lateral (90.7%) and an anterolateral (9.3%) approach was applied. On pelvic radiographs, a nested-controlled analysis was performed. Two control patients were matched to one patient suffering a dislocation with respect to age, sex, and body-mass-index (BMI).

Results

In 527 HHA, 10 dislocations (1.9%) were identified. In the dislocation group (DG), all patients were female (100% vs. 73.5%, p = 0.071). No significant differences between the DG and the control group (CG) were found with respect to age, body-mass-index (BMI), ASA Score, routine laboratory parameters, and comorbidity. Radiographic analysis revealed a smaller center edge angle (CEA, 39.0, IQR 33.0–42.5 vs. 43.0, IQR 41.0–46.0, p = 0.013), a more varus neck-shaft angle (NSA, 130.0, IQR 125.8–133.5 vs. 135.0, IQR 134.0–137.0, p = 0.011) of the contralateral side and a higher femoral head extrusion index (FHEI) in the DG (FHEI, 11.5, IQR 9.8–16.3 vs. 2.0 IQR 0.0–9.0, p = 0.003). In addition, a greater trochanteric fracture was associated with an increased likelihood for HHA dislocations (30.0% vs 6.0%, p = 0.022).

Conclusion

A smaller radiographic center edge angle, a more varus neck-shaft angle of the contralateral side, a higher femoral head extrusion index and intraoperative fractures of the greater trochanter are associated with an increased risk of HHA dislocation.

Is there a higher risk of dislocation of hip hemiarthroplasty in patients with neuromuscular conditions? A clinical study of 3827 patients

AIM OF THE STUDY

The aim of this study is to identify if there is any association between neuromuscular disorders and prosthetic dislocation in patients treated with hip hemiarthroplasty for neck of femur fractures.

PATIENTS AND METHODS

Our study is a retrospective analysis of data collected over 34 years for patients with intracapsular neck of femur fracture who underwent hip hemiarthroplasty. Pathological fractures and patients treated with other treatment modalities were excluded. The study population is composed of four groups; patients with no neuromuscular disorders, patients with Parkinson's disease, patients with previous stroke, and patients with mental impairment.

RESULTS

A total of 3827 patients were treated with hip hemiarthroplasty. For the 3371 patients with no neuromuscular condition (Group I) the dislocation rate was 1.1%. 219 patients had Parkinsonism (Group II) with a dislocation rate of 3.2%, 104 patients had a previous stroke with weakness on the fracture side with a dislocation rate of 1.0% (Group III), and 984 patients had severe mental impairment with a dislocation rate of 1.8% (Group IV). The increased dislocation rate for those with Parkinson's disease was statistically significant (p = 0.02) while none of the other neuromuscular conditions were statistically significant.

CONCLUSION

Our study demonstrates an increased risk of dislocation after hemiarthroplasty for patients with Parkinson's disease in comparison to other groups. No increase was apparent for those with mental impairment or weakness from a previous stroke.

Outcomes of dual-mobility total hip arthroplasty versus bipolar hemiarthroplasty for patients with femoral neck fractures: a systematic review and meta-analysis

Background

Elderly patients with femoral neck fractures are at a higher risk of dislocation after hip arthroplasty procedures. In comparison with total hip arthroplasty (THA), bipolar hemiarthroplasty (HA) and dual-mobility total hip arthroplasty (DM-THA) can be an effective alternative treatment which increases the effective head size and overall stability of the prosthesis. We aim to review the current evidence on the outcome after DM-THA and HA for femoral neck fractures in the elderly.

Methods

We performed a comprehensive review of literatures on PubMed, Embase, Web of Science, and the Cochrane Library for randomized controlled trials and comparative interventional studies. Of the 936 studies identified, 8 met the inclusion criteria (541 DM-THA and 603 HA procedures). Two reviewers independently reviewed and graded each study and recorded relevant data including dislocation rate, implant failure rate, reoperation rate, 1-year mortality rate, Harris hip score (HHS), operation time, and intraoperative blood loss.

Results

DM-THA was associated with a lower dislocation rate (OR 3.599; 95% CI 1.954 to 6.630), a lower reoperation rate (OR 2.056; 95% CI 1.211 to 3.490), an increased operation time (SMD − 0.561; 95% CI − 0.795 to − 0.326) and more intraoperative blood loss (SMD − 0.778; 95% CI − 1.238 to − 0.319), compared with the HA group. Moreover, the multivariate regression analysis revealed that age, female sex, posterolateral surgical approach, and choice of DM-THA or HA were not associated with dislocation or reoperation.

Conclusions

Based on the current evidence, the advantages reported for DM-THA over HA with regard to dislocation and reoperation rate in elderly patients with FNF remain inconclusive. High-quality studies on the high-risk patients with cognitive disorder or dementia are necessary to validate the value of DM-THA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02316-6.

Risk factors for dislocation after bipolar hemiarthroplasty: a retrospective case-control study of patients with CT data

Purpose

Bipolar hemiarthroplasty has been shown to have a lower rate of dislocation than total hip arthroplasty. However, as the influencing risk factors for bipolar hemiarthroplasty dislocation remain unclear, we aimed to analyse patient and surgeon-specific influencing risk factors for bipolar hemiarthroplasty dislocation.

Methods

We retrospectively analysed patients who were operated between 2012 and 2018 and had dislocated bipolar hemiarthroplasty and matched them to patients without a dislocated bipolar hemiarthroplasty, operated between 2018 and 2019. The study was limited to patients who received either a pre- or postoperative pelvic computed tomography. Besides demographic, morphologic, and physiologic data, we analysed duration of surgery; ASA score; Charlson Comorbidity Index; Almelo Hip Fracture Score; Parker Score; and acetabular morphology angles including acetabular anteversion angle, posterior acetabular sector angle, posterior wall angle, and acetabular roofing.

Results

We included nine patients with a dislocated bipolar hemiarthroplasty and 30 with a non-dislocated bipolar hemiarthroplasty. Patient-specific factors prompting a higher risk for dislocated bipolar hemiarthroplasty were longer duration of surgery (min) (115 ± 50 vs. 80 ± 27, p = 0.01); dementia (56% vs. 13%, p < 0.01); smaller posterior acetabular sector angle (°) (96 ± 6 vs. 109 ± 10, p < 0.01); and smaller posterior wall angle (°) (67 ± 6 vs. 77 ± 10, p = 0.02).

Conclusion

Dementia and insufficient posterior wall angle were associated with higher risk of dislocation in bipolar hemiarthroplasty