The conversion rate of bipolar hemiarthroplasty after a hip fracture to a total hip arthroplasty

Femoral Neck Fractures: Incidence, Reasons, and Risk Factors of Conversion From Hemiarthroplasty to Total Hip Arthroplasty

BACKGROUND

There is controversy over the choice of hemiarthroplasty (HA) versus total hip arthroplasty for treatment of femoral neck fractures in geriatric patients, especially those who are relatively healthy and active. A concern for selection of HA is that the patients may later require conversion to THA.

METHODS

All geriatric patients with femoral neck fractures who underwent HA were identified in the national PearlDiver data set. Patients were required to have 5 years of follow-up, and incidence of conversion was determined. Univariable and multivariable analyses were conducted to determine factors associated with conversion. The timing of conversion and reasons for conversions were determined.

RESULTS

A total of 7,501 patients were identified with femoral neck fractures who underwent initial treatment with HA. Of those, 173 (2.3%) underwent conversion to THA within 5 years. On multivariable analysis, conversion was associated with patients being younger than 75 years (odds ratio: 1.64, P = 0.002) and having a higher Elixhauser Comorbidity Index (odds ratio: 1.04 per point, P = 0.018). Of the conversions performed over a five year period, 109 patients (63.0%) were within the 1st year. The most common reason for conversion to THA was degenerative causes (67.6%).

CONCLUSIONS

Overall, there was a low rate (2.3%) of conversion from HA to THA for those who were tracked for 5 years after HA for femoral neck fracture. This low conversion rate is supportive that HA offers a durable answer for most patients for whom this treatment choice is pursued.

LEVELS OF EVIDENCE

III.

Symptomatic Acetabular Erosion After Hip Hemiarthroplasty: Is It a Major Concern? A Retrospective Analysis of 2477 Hemiarthroplasty Cases

Background/Objectives: Acetabular erosion is a postoperative condition that can occur after hip hemiarthroplasty (HA), potentially leading to pain and requiring conversion to total hip arthroplasty (THA). Given the discrepancy in its incidence and impact in the literature, this study aims to report the incidence of symptomatic acetabular erosion and the subsequent conversion to THA in all HA cases performed in a single health system. Methods: A total of 2477 HA cases had their clinical notes and serial radiographs examined for this retrospective study. Outcome measures included any records of hip or groin pain and conversion to THA that were attributed to acetabular erosion as documented in the clinical notes. Results: Two thousand four hundred and seventy-seven HA cases were reviewed in this study. The mean age for all patients in the study was 81.5 years and the mean follow up was 3.7 years. Out of the 2477 HA cases, only 12 HA cases (0.48%) in 12 patients had data records of chronic hip pain, attributable to acetabular wear in the clinical notes, of variable severity and presentations. The mean duration until the clinical documentation of acetabular wear-induced pain was 25.6 months (range, 1.4-146.4 months), with most symptomatic hip erosion cases presented within the first year (50% presented within the first 6 months) after the index HA surgery. Despite that, only five cases underwent conversion to THA (0.2%) while seven patients received conservative management. Conclusions: In patients older than 65 years of age who are candidates for HA, the incidence of symptomatic hip erosion and the subsequent conversion to THA is low and hence HA remains a viable treatment option. Based on the duration until clinical presentation of acetabular erosion, this study suggests that the state of acetabular cartilage during surgery may influence the development of early acetabular wear in most symptomatic patients. On the other hand, hip hemiarthroplasty is a rare treatment option for displaced femoral neck fractures in patients younger than 65 years of age, and its use in this patient subset depends on conditional and patient-related factors such as the activity level, cognitive function, and medical comorbidities.

Arthroplasty for femoral neck fractures is at risk for under restoration of lateral femoral offset

PURPOSE

The aim of the study was to determine the restoration of hip biomechanics through lateral offset, leg length, and acetabular component position when comparing non-arthroplasty surgeons (NAS) to elective arthroplasty surgeons (EAS).

METHODS

131 patients, with a femoral neck fracture treated with a THA by 7 EAS and 20 NAS, were retrospectively reviewed. 2 blinded observers measured leg-length discrepancy, femoral offset, and acetabular component position. Multivariate logistic regression models examined the association between the surgeon groups and restoration of lateral femoral, acetabular offset, leg length discrepancy, acetabular anteversion, acetabular position, and component size, while adjusting for surgical approach and spinal pathology.

RESULTS

NAS under-restored 4.8 mm of lateral femoral offset (43.9 ± 8.7 mm) after THA when compared to the uninjured side (48.7 ± 7.1 mm, p = 0.044). NAS were at risk for under-restoring lateral femoral offset when compared to EAS (p = 0.040). There was no association between lateral acetabular offset, leg length, acetabular position, or component size and surgeon type.

CONCLUSIONS

Lateral femoral offset is at risk for under-restoration after THA for femoral neck fractures, when performed by surgeons that do not regularly perform elective THA. This indicates that lateral femoral offset is an under-appreciated contributor to hip instability when performing THA for a femoral neck fracture. Lateral femoral offset deserves as much attention and awareness as acetabular component position since a secondary analysis of our data reveal that preoperative templating and intraoperative imaging did not prevent under-restoration.

Comparison of Differences in Complications and Revision After Conversion to Total Hip Arthroplasty from Plating vs. Nailing vs. Hemiarthroplasty

BACKGROUND

Total hip arthroplasty (THA)after previous hip surgery increases the procedure complexity and complication rate. We investigated the complication rates following conversion to total hip arthroplasty from three hip surgeries, namely plate fixation of the intertrochanteric fracture, nailing of the trochanteric fracture, and hemiarthroplasty of the hip.

METHODS

This retrospective study was conducted using the PearlDiver database (www.pearldiverinc.com, Colorado Springs) and identified all patients undergoing THA between 2010 and 2019. Among this group, we included all patients who had received one of the three procedures , hip hemiarthroplasty (CPT 27125), fixation of the intertrochanteric fracture with plates and screws (CPT 27444), or fixation of hip fracture with nail (CPT 27445) within two years of THA. We analyzed complications in these patients and compared it to the complication rate in primary THA patients. The complications analyzed were 30-day transfusion risk, 90-day surgical site infection (SSI) risk, 90-day periprosthetic fracture risk, 1-year dislocation risk, and 2-, 5-, and 10-year revision risk.

RESULTS

A total of 118,209 patients underwent THA between 2010 and 2019. A total of 9,173, 48,326, and 31,632 patients underwent fixation with plates and screws , nailing and hemiarthroplasty respectively. We identified 71, 42, and 160 patients with hemiarthroplasty, plates & screws, and nailing, respectively, within two years of THA. 117,936 primary THA patients were used as a comparison group. The nailing group had the highest rate of transfusion risk (OR=2.34, 95% CI=1.32, 4.13, P<0.05).Furthermore, the hemiarthroplasty group had highest rate of SSI risk (OR=9.25, 95% CI=4.86, 17.63, P<0.05) and highest revision risk at 2 years (OR=10.532, 95% CI= 6.09, 18.19, P<0.05).

CONCLUSION

Conversion of hemiarthroplasty to THA was associated with a higher risk of infection and revision. Hence, surgeons considering primary hip hemiarthroplasty for severely comminuted intertrochanteric fracture should exercise caution, especially for active elderly patients.

Dissociation of Bipolar Hemiarthroplasty of the Hip and Review of Literature

Component dissociation after a bipolar hemiarthroplasty is an uncommon complication that usually necessitates reoperation due to difficulties in closed reduction. To our knowledge, only a few cases have been published in the recent literature. We present a case of disassembly location of in a 68-year-old woman who underwent bipolar hemiarthroplasty 10 years ago due to a left hip femoral neck fracture. She began complaining about pain and difficulty to bear weight after an unintentional internal rotation movement of her left hip. The initial radiographs showed the disassembly of the bipolar hip prosthesis, and the patient underwent conversion to total hip arthroplasty. We conducted a literature review to explain the potential causes and mechanisms.

High conversion rate to total hip arthroplasty after hemiarthroplasty in young patients with a minimum 10 years follow-up

Background

This study aimed to evaluate the follow-up results of bipolar hemiarthroplasty (BHA) for more than 10 years in patients aged < 60 years and to analyze the risk factors for acetabular erosion after BHA.

Methods

This retrospective study included 114 patients who underwent BHA were followed-up for at least 10 years. The mean age was 54.1 years, and the mean follow-up duration was 13.8 years. The patients were divided into two groups according to the presence of acetabular erosion, and the preoperative parameters were compared between the two groups. Moreover, the risk factors related to acetabular erosion after BHA were analyzed using statistical comparisons.

Results

Reoperation was performed in 44 of the 114 patients (38.6 %). The survival rate when the end point was reoperation related to acetabular erosion was found to be significantly time-dependent: 73.2 % at 5 years, 48.8 % at 10 years, and 25.9 % at 15 years. The acetabular erosion group showed significantly younger age at the time of surgery, higher body mass index (BMI), more avascular necrosis of the femoral head, and smaller prosthetic femoral head. The final multivariate logistic regression analysis showed that young age at the time of surgery were independent risk factors for acetabular erosion after BHA in patients aged < 60 years.

Conclusions

The minimum 10-year follow-up outcomes of BHA in patients aged < 60 years showed a relatively high conversion rate to total hip arthroplasty. When considering BHA in younger patients, more careful decisions should be made with respect to patient’s choice, keeping in mind that long-term survival cannot be guaranteed.

Hemiarthroplasty Conversion: A Comparison to Primary and Revision Total Hip Arthroplasty

BACKGROUND

Arthroplasty is the standard of care for elderly patients with displaced femoral neck fractures, with viable options including hemiarthroplasty (HA) and total hip arthroplasty (THA). With time, HA may need to be converted to THA, but it is unclear whether this is more similar to primary or revision THA. We compare complication and revision rates between these groups within 90 days and 2 years postoperatively.

METHODS

We retrospectively reviewed 3 cohorts of patients treated at our institution: primary, conversion, and revision THA. Outcomes studied included intraoperative data, postoperative complications, and revision rates. We analyzed the groups using both parametric (analysis of variance test) and nonparametric (chi-squared test) statistics.

RESULTS

Operative time between primary THA (108.0 minutes), conversion HA (147.9 minutes), and revision THA (160.1 minutes) cohorts differed significantly (P = .011). Estimated blood loss was also different between primary THA (386 mL), conversion HA (587 mL), and revision THA cohorts (529 mL) (P = .011). At 2 years, major complication rates between primary THA (6.2%), conversion HA (11.7%), and revision THA (26.7%) cohorts also differed significantly (P = .003), as was the revision rate in the primary THA (4.6%), conversion HA (10.0%), and revision THA (18.3%) cohorts (P = .043).

CONCLUSION

This is the first study to compare short-term and midterm complications between primary, conversion, and revision THA. We observed conversion HA had similar operative time and estimated blood loss to revision THA, which was significantly higher than primary THA. However, we found that conversion HA more closely resembled primary THA with respect to perioperative complications rates.

Conversion of Failed Hip Hemiarthroplasty to Low Friction Arthroplasty (LFA)

Purpose: We aimed to study clinical and radiological outcomes of conversion from hemiarthroplasty to Charnley hip replacement (CHR) with a particular concern over reported increased dislocation rate and literature review. Conversion of hip hemiarthroplasty to total hip replacement (THR) is a procedure reported to have high rates of complications. In the literature, there is no specific study on small head conversion. The purpose of this study was to evaluate the conversion of failed hip hemiarthroplasty to CHR with the use of modern implants. Methods: The study included 42 patients, who underwent the above procedure. The operations were carried out using a modern Charnley-type THR with a 22-mm diameter of femoral head and a trans-trochanteric approach. The mean follow-up was 75.7 months (range 25–171). Radiographs from the last follow up were evaluated for loosening and other reasons of failure. Clinical outcome was assessed using postoperative pain, function scores, complications and implant survivorship as well as radiological evaluation. Charnley’s modified pain and mobility scoring system were used for clinical and Hodgkinson and Harris’ criteria were used for radiological assessment. Results: Functionally, all of the patients showed improvement. Mean improvement in the pain level was by average of 2.4. On mobility assessment, 38 patients (90.4%) improved. Three patients (7.1%) had recurrent infections and three (4.8%) cases were treated with revision surgery and pseudarthrosis. Further complications occurred in 19.1%, not requiring operative treatment. On radiological evaluation, one (2.4%) case showed cup demarcation without bone loss, two (4.8%) cup migration, and one (2.4%) stem demarcation. Kaplan Meier survival analysis showed a survival of 90% at 96 months of follow up (95% CI (confidence interval), 60–90). Conclusion: Larger head might not be the answer to decrease the dislocation rate. Complication rates during revision of hip hemiarthroplasty to modern CHR with 22.225-mm head diameter were comparable to first-time THR revision despite having a smaller head.

Reasons for revision of failed hemiarthroplasty: Are there any differences between unipolar and bipolar?

BACKGROUND

Hemiarthroplasty (HA) is an effective procedure for treatment of femoral neck fracture. However, it is debatable whether unipolar or bipolar HA is the most suitable implant.

OBJECTIVE

The purpose of this study was to compare the causes of failure and longevity in both types of HA.

MATERIALS AND METHODS

We retrospectively reviewed 133 cases that underwent revision surgery of HA between 2002 and 2012. The causes of revision surgery were identified and stratified into early (≤ 5 years) failure and late (> 5 years) failure. Survival analyses were performed for each implant type.

RESULTS

The common causes for revision were aseptic loosening (49.6%), infection (22.6%) and acetabular erosion (15.0%). Unipolar and bipolar HA were not different in causes for revision, but the unipolar group had a statistically significantly higher number of acetabular erosion events compared with the bipolar group (p = 0.002). In the early period, 24 unipolar HA (52.9%) and 28 bipolar HA (34.1%) failed. There were no statistically significant differences in the numbers of revised HA in each period between the two groups (p = 0.138). The median survival times in the unipolar and bipolar groups were 84.0 ± 24.5 and 120.0 ± 5.5 months, respectively. However, the survival times of both implants were not statistically significantly different.

CONCLUSIONS

Aseptic loosening was the most common reason for revision surgery after hemiarthroplasty surgery in early and late failures. Unipolar and bipolar hemiarthroplasty were not different in terms of causes of failure and survivorship except bipolar hemiarthroplasty had many fewer acetabular erosion events.

Risk factors for conversion surgery to total hip arthroplasty of a hemiarthroplasty performed for a femoral neck fracture

INTRODUCTION

The purpose of this study was to determine risk factors for conversion to total hip arthroplasty (THA) in patients originally treated with hemiarthroplasty (HA) for displaced femoral neck fractures.

METHODS

In this case-controlled study, we identified 54 patients who were treated with HA for femoral neck fracture (FNF) who subsequently underwent conversion to THA at our institution between 2003 and 2013. We randomly selected 142 control patients who underwent HA for a displaced FNF without conversion surgery during the same time period. We compared demographic data, implant parameters, and radiographic data between the groups to identify risk factors for conversion surgery.

RESULTS

In the univariate analysis, younger age at index surgery (mean 75 vs. 80 years, p = 0.006), higher body mass index (26.1 vs. 23.7, p = 0.031), bipolar prosthesis (20% vs. 36%, p = 0.024), absence of dementia (6% vs. 23%, p = 0.01), increased leg length compared to contralateral limb (6.5 mm vs. 0.2 mm, p<0.001), and increased HA femoral head size compared to the contralateral femoral head (2.7 mm vs. 1.5 mm, p = 0.02) were associated with a significantly increased risk of conversion surgery. In the multivariate logistic regression, decreased age at index surgery, no dementia, use of a bipolar head, and increased leg length discrepancy (LLD) were associated with risk of conversion.

CONCLUSIONS

Patient characteristics, including younger age, increased BMI, and absence of dementia can lead to increased risk for conversion of HA to THA. Intraoperative considerations of head size and increase in ipsilateral LLD may increase the risk of conversion surgery. These factors should be considered by surgeons who employ HA for displaced FNFs.

Risk factors for conversion surgery to total hip arthroplasty of a hemiarthroplasty performed for a femoral neck fracture

INTRODUCTION

The purpose of this study was to determine risk factors for conversion to total hip arthroplasty (THA) in patients originally treated with hemiarthroplasty (HA) for displaced femoral neck fractures.

METHODS

In this case-controlled study, we identified 54 patients who were treated with HA for femoral neck fracture (FNF) who subsequently underwent conversion to THA at our institution between 2003 and 2013. We randomly selected 142 control patients who underwent HA for a displaced FNF without conversion surgery during the same time period. We compared demographic data, implant parameters, and radiographic data between the groups to identify risk factors for conversion surgery.

RESULTS

In the univariate analysis, younger age at index surgery (mean 75 vs. 80 years, p = 0.006), higher body mass index (26.1 vs. 23.7, p = 0.031), bipolar prosthesis (20% vs. 36%, p = 0.024), absence of dementia (6% vs. 23%, p = 0.01), increased leg length compared to contralateral limb (6.5 mm vs. 0.2 mm, p<0.001), and increased HA femoral head size compared to the contralateral femoral head (2.7 mm vs. 1.5 mm, p = 0.02) were associated with a significantly increased risk of conversion surgery. In the multivariate logistic regression, decreased age at index surgery, no dementia, use of a bipolar head, and increased leg length discrepancy (LLD) were associated with risk of conversion.

CONCLUSIONS

Patient characteristics, including younger age, increased BMI, and absence of dementia can lead to increased risk for conversion of HA to THA. Intraoperative considerations of head size and increase in ipsilateral LLD may increase the risk of conversion surgery. These factors should be considered by surgeons who employ HA for displaced FNFs.

Steady state acetabular cartilage wear after bipolar hemiarthroplasty: a case series of 10 patients with radiostereometric analysis

INTRODUCTION

Cartilage wear is a concern after hemiarthroplasty. The precise pattern of the progression of wear has not been evaluated. We previously reported the application of radiostereonetric analysis (RSA) for the measurement of cartilage wear in patients. The purpose of this study was to report the amount and the orientation of the steady state wear of cartilage between 1 and 3 years after bipolar hemiarthroplasty.

METHODS

22 patients with a bipolar hemiarthroplasty for displaced femoral neck fracture were included. 10 patients completed the mean follow up of 37 months. The cartilage wear was evaluated by calculating the migration of the bipolar head in reference to the markers in the acetabulum using RSA.

RESULTS

The mean age of the patients at the final follow-up was 80 (range 67-91) years. The 3-D migration was -0.02 mm (SD 0.30) between 1 and 3 years. The migration in each direction was 0.03 mm (SD 0.49) in medial, 0.03 mm (SD 0.14) in proximal and 0.11 mm (SD 0.29) in posterior directions. 2 patients showed migration of more than 0.2 mm. The large initial migration seen in some patients up to 1 year did not progress further. Total wear after 37 months was 0.43 mm (SD 0.17).

CONCLUSIONS

Cartilage wear progressed slowly in 2 of 10 patients from 1 to 3 years. No pelvic penetration was seen. We believe that RSA will give a basic knowledge about the development and the progression of cartilage wear after hemiarthroplasty.

Hemiarthroplasty for Displaced Femoral Neck Fractures in the Elderly Has a Low Conversion Rate

BACKGROUND

Hemiarthroplasty (HA) has been a mainstay treatment for displaced femoral neck fractures for many years. The purpose of this study was to report the conversion rate of HA to total hip arthroplasty (THA) for displaced femoral neck fractures and compare outcomes between implant constructs (bipolar vs unipolar), fixation options (cemented vs cementless stems), and age groups (<75 years vs ≥75 years).

METHODS

We retrospectively reviewed the results of a consecutive cohort of 686 patients who underwent HA for the treatment of femoral neck fractures at our institution between 1999 and 2013 with a minimum of 2-year follow-up.

RESULTS

The overall component revision rate, including conversion to THA, revision HA, revision with open reduction internal fixation, and Girdlestone procedure, was 5.6% (39/686). Seventeen patients (2.5%) were converted from HA to THA at an average of 1.9 years after index procedure. A significantly lower conversion rate of 1.4% (7/499 patients) was found in the older patient cohort (≥75 years old) compared to 5.3% (11/187) in the younger cohort. The most common causes for conversion surgery to THA were acetabular wear (5 patients), aseptic loosening (4 patients), and periprosthetic fracture (3 patients). There was a significantly lower rate of periprosthetic fracture (0.4% vs 2.5%, P value .025) in the cemented implant group compared to the cementless group. We observed a higher rate of dislocations in the bipolar vs unipolar group (3.8% vs 1%, P value .02) and no other significant differences between these groups.

CONCLUSION

We observed a low reoperation rate for this cohort of patients, relatively higher conversion rates for the younger population, fewer periprosthetic fractures with the use of cemented stems, and no advantage of bipolar over unipolar prostheses.

Recent advances in the treatment of hip fractures in the elderly

The treatment of hip fractures in the elderly represents a major public health priority and a source of ongoing debate among orthopaedic surgeons and anesthesiologists. Most of these injuries are treated with surgery in an expedient fashion. From the surgical perspective, there are certain special considerations in this population including osteoporosis, pre-existing arthritis, age, activity level, and overall health that contribute to the type of surgical fixation performed. Open reduction and internal fixation versus arthroplasty remain the two major categories of treatment. While the indications and treatment algorithms still remain controversial, the overall goal for these patients is early mobilization and prevention of morbidity and mortality. The use of preoperative, regional anesthesia has aided in this effort. The purpose of this review article is to examine the various treatment modalities for hip fractures in the elderly and discuss the most recent evidence in the face of a rapidly aging population.

The Cemented Unipolar Prosthesis for the Management of Displaced Femoral Neck Fractures in the Dependent Osteopenic Elderly

BACKGROUND

Significant variability exists across orthopedic surgeons in the management of the displaced femoral neck fracture in the elderly patient (>75 years old). These patients tend to be less healthy, have inferior bone quality, and gait instability leading to increased risk of periprosthetic fracture, compromised implant fixation, dislocation, and need for revision. The surgeon's goals should be to restore mobility while eliminating pain and need for reoperation.

METHODS

In this review article, we examine the best available evidence in the literature to determine which strategy achieves optimal outcomes. We examine outcome studies comparing use of hemiarthroplasty and total hip arthroplasty, unipolar and bipolar hemiarthroplasty, and cemented vs cementless fixation of femoral stems.

RESULTS AND CONCLUSIONS

For the active, healthy, and lucid patient, or one who has preexisting groin pain, who sustains a displaced femoral neck fracture, the literature supports a total hip arthroplasty. Patients sustaining a displaced femoral neck fracture and who are less active, have decreased bone mass, and are at increased risk of falls would benefit most from a device that optimally balances the need for revision surgery, restores ambulation, and eliminates pain. Thus, the current evidence favors cemented, unipolar hemiarthroplasty for the dependent osteopenic elderly patient with a displaced femoral neck fracture.

The effect of osteoarthritis on functional outcome following hemiarthroplasty for femoral neck fracture: a prospective observational study

BACKGROUND

The influence of pre-existing radiographic osteoarthritis on the functional outcome of elderly patientents with displaced intracapsular fractures of the femoral neck treated by hemiarthroplasty is unclear.

METHODS

We prospectively examined the impact of pre-existing osteoarthritis on the functional outcome of 126 elderly patients with displaced intracapsular fracture of the femoral neck treated by hemiarthroplasty.

RESULTS

The mean age of the cohort was 82.7 years. At 12 months, we observed no statistically significant differences in the Harris hip score (p = 0.545), the timed up and go test (p = 0.298), the Tinetti test (p = 0.381) or the Barthel Index (p = 0.094) between patients with Kellgren and Lawrence grades 3 or 4 osteoarthritis, and patients with grades 0 to 2 changes. Furthermore, there were no differences in complication or revision rates.

CONCLUSIONS

Our findings challenge the hypothesis that pre-existing osteoarthritis is a contraindication to hemiarthroplasty in elderly patients with femoral neck fracture.

Uni- and bipolar hemiarthroplasty with a modern cemented femoral component provides elderly patients with displaced femoral neck fractures with equal functional outcome and survivorship at medium-term follow-up

INTRODUCTION

The choice between unipolar and bipolar hemiarthroplasty for treatment of displaced intracapsular femoral neck fractures in elderly patients still remains controversial. Our objective was to compare series of elderly individuals with a displaced femoral neck fracture treated with either a cemented, modular unipolar or bipolar prosthesis with the same femoral component.

MATERIALS AND METHODS

A prospective, randomized controlled trial of 175 displaced intracapsular femoral neck fractures in patients over 65 years was randomly allocated to unipolar (88) and to bipolar (87) hemiarthroplasty group. The primary end point was implant survival. Secondary end points included difference in ambulatory ability and mortality. Follow-up evaluations were performed at 2 months, at 1, 3 and 5 years. Implant and patient survival were followed until 2/2012. Survival analyses were performed using Kaplan-Meier curves with log-rank test. Data were analyzed using Chi-square test and Student's t test.

RESULTS

Unipolar hemiarthroplasty group had a significantly higher dislocation rate when compared with bipolar hemiarthroplasty group. This did not translate into difference in revision rates at 8 years. Prosthetic survival ship was 0.98 (95% Cl 0.94-1.00) in the unipolar group and 0.97 (95% Cl 0.93-1.00) in the bipolar group. There were no statistically significant differences in ambulatory ability, possibility to return home mortality or early radiological acetabular erosion. There were significantly more one-time dislocations in the unipolar group, but there was no difference in incidence of revisions due to recurrent dislocations. The overall mortality rate was 6% at 30 days, 9% at 90 days, 16% at 12 months, and 53% at 5 years. There was no difference in mortality between the groups.

CONCLUSIONS

Unipolar hemiarthroplasty group had a significantly higher dislocation rate when compared with bipolar hemiarthroplasty group. However, both provide elderly patients with equal ambulatory ability and low revision rate at medium-term follow-up.