Orthopedics

CME Review Article 

Unipolar Versus Bipolar Hemiarthroplasty for Displaced Femoral Neck Fractures in Elderly Patients

Zhiping Zhou, MD; Fei Yan, MD; Weiping Sha, MD; Liming Wang, MD; Xingxiang Zhang, MD

Abstract

Educational Objectives

As a result of reading this article, physicians should be able to:

Discuss the treatment of femoral neck fractures in elderly patients.

State the indications for hemiarthroplasty.

Describe the advantages and disadvantages of unipolar and bipolar femoral head replacement.

Discuss progress regarding clinical comparative studies of femoral head replacement.

Hip replacement using hemiarthroplasty (HA) is a common surgical procedure in elderly patients with femoral neck fractures. However, questions remain regarding the choice of unipolar or bipolar HA. A meta-analysis of randomized, controlled trials (RCTs) was performed to determine whether bipolar HA was associated with lower rates of dislocation, reoperation, acetabular erosion, mortality, and general complications, as well as lower Harris Hip Scores, compared with unipolar HA. The authors searched PubMed and the Cochrane Register of Controlled Trials database, and 8 RCTs (including a total of 1100 patients) were selected for meta-analysis. Risk ratios (RRs) and weighted mean differences (WMDs) from each trial were pooled using random-effects or fixed-effects models depending on the heterogeneity of the included studies. There were no differences in dislocation (RR=1.20; 95% confidence interval [CI], 0.47 to 3.07), reoperation (RR=0.64; 95% CI, 0.33 to 1.26), acetabular erosion (RR=2.29; 95% CI, 0.85 to 6.12), mortality (RR=0.85; 95% CI, 0.63 to 1.13), and general complications (RR=1.05; 95% CI, 0.70 to 1.56). The authors found no difference in postoperative Harris Hip Scores between patients undergoing unipolar vs bipolar HA (WMD=−1.32; 95% CI, −3.29 to 0.65; P=.19). Unipolar and bipolar HA achieved similar clinical outcomes in patients with displaced femoral neck fractures. [Orthopedics. 2015; 38(11):697–702.]

CME Accreditation

This activity has been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education through the joint sponsorship of Keck School of Medicine of USC and Orthopedics. Keck School of Medicine of USC is accredited by the ACCME to provide continuing medical education for physicians.

Keck School of Medicine of USC designates this Journal-based CME activity for a maximum of 1 AMA PRA Category 1 Credit™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

This CME activity is primarily targeted to orthopedic surgeons, hand surgeons, head and neck surgeons, trauma surgeons, physical medicine specialists, and rheumatologists. There is no specific background requirement for participants taking this activity.

Full Disclosure Policy

In accordance with the Accreditation Council for Continuing Medical Education's Standards for Commercial Support, all CME providers are required to disclose to the activity audience the relevant financial relationships of the planners, teachers, and authors involved in the development of CME content. An individual has a relevant financial relationship if he or she has a financial relationship in any amount occurring in the last 12 months with a commercial interest whose products or services are discussed in the CME activity content over which the individual has control.

The authors have no relevant financial relationships to disclose. Dr Aboulafia, CME Editor, has no relevant financial relationships to disclose. Dr D'Ambrosia, Editor-in-Chief, has no relevant financial relationships to disclose. The staff of Orthopedics have no relevant financial relationships to disclose.

Unlabeled and Investigational Usage

The audience is advised that this continuing medical education activity may contain references to unlabeled uses of FDA-approved products or to products not approved by the FDA for use in the United States. The faculty members have been made aware of their obligation to disclose such usage.

 

Abstract

Educational Objectives

As a result of reading this article, physicians should be able to:

Discuss the treatment of femoral neck fractures in elderly patients.

State the indications for hemiarthroplasty.

Describe the advantages and disadvantages of unipolar and bipolar femoral head replacement.

Discuss progress regarding clinical comparative studies of femoral head replacement.

Hip replacement using hemiarthroplasty (HA) is a common surgical procedure in elderly patients with femoral neck fractures. However, questions remain regarding the choice of unipolar or bipolar HA. A meta-analysis of randomized, controlled trials (RCTs) was performed to determine whether bipolar HA was associated with lower rates of dislocation, reoperation, acetabular erosion, mortality, and general complications, as well as lower Harris Hip Scores, compared with unipolar HA. The authors searched PubMed and the Cochrane Register of Controlled Trials database, and 8 RCTs (including a total of 1100 patients) were selected for meta-analysis. Risk ratios (RRs) and weighted mean differences (WMDs) from each trial were pooled using random-effects or fixed-effects models depending on the heterogeneity of the included studies. There were no differences in dislocation (RR=1.20; 95% confidence interval [CI], 0.47 to 3.07), reoperation (RR=0.64; 95% CI, 0.33 to 1.26), acetabular erosion (RR=2.29; 95% CI, 0.85 to 6.12), mortality (RR=0.85; 95% CI, 0.63 to 1.13), and general complications (RR=1.05; 95% CI, 0.70 to 1.56). The authors found no difference in postoperative Harris Hip Scores between patients undergoing unipolar vs bipolar HA (WMD=−1.32; 95% CI, −3.29 to 0.65; P=.19). Unipolar and bipolar HA achieved similar clinical outcomes in patients with displaced femoral neck fractures. [Orthopedics. 2015; 38(11):697–702.]

CME Accreditation

This activity has been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education through the joint sponsorship of Keck School of Medicine of USC and Orthopedics. Keck School of Medicine of USC is accredited by the ACCME to provide continuing medical education for physicians.

Keck School of Medicine of USC designates this Journal-based CME activity for a maximum of 1 AMA PRA Category 1 Credit™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

This CME activity is primarily targeted to orthopedic surgeons, hand surgeons, head and neck surgeons, trauma surgeons, physical medicine specialists, and rheumatologists. There is no specific background requirement for participants taking this activity.

Full Disclosure Policy

In accordance with the Accreditation Council for Continuing Medical Education's Standards for Commercial Support, all CME providers are required to disclose to the activity audience the relevant financial relationships of the planners, teachers, and authors involved in the development of CME content. An individual has a relevant financial relationship if he or she has a financial relationship in any amount occurring in the last 12 months with a commercial interest whose products or services are discussed in the CME activity content over which the individual has control.

The authors have no relevant financial relationships to disclose. Dr Aboulafia, CME Editor, has no relevant financial relationships to disclose. Dr D'Ambrosia, Editor-in-Chief, has no relevant financial relationships to disclose. The staff of Orthopedics have no relevant financial relationships to disclose.

Unlabeled and Investigational Usage

The audience is advised that this continuing medical education activity may contain references to unlabeled uses of FDA-approved products or to products not approved by the FDA for use in the United States. The faculty members have been made aware of their obligation to disclose such usage.

 

Hip fractures in older patients are associated with impaired mobility, high rates of morbidity and mortality, and loss of independence.1 Thus, hip fractures remain a public health concern, especially with the aging population and the high incidence of osteoporosis.1,2 Displaced femoral neck fractures are one of the most common hip fractures, and they generally need surgical intervention. The goals of surgical treatment are immediate pain relief, rapid mobilization, accelerated rehabilitation, and a low risk of surgical complications or subsequent revision.3

Optimal treatment of femoral neck fractures has been controversial for years. One debate is unipolar (fixed-head) vs bipolar (universal) endoprosthesis for the treatment of displaced (Garden types III through IV) femoral neck fractures in elderly patients. The bipolar prosthesis has a theoretical advantage because it was designed to move at its inner bearing in addition to articulating at the prosthesis-acetabulum interface. This should decrease the amount of acetabular erosion and reduce pain. However, several studies4,5 have shown that the inner bearing loses mobility with time and becomes stiff, thereby minimizing the advantage of the bipolar prosthesis. Furthermore, the increased cost of the bipolar prosthesis compared with the unipolar prosthesis raises the question of whether the difference in cost translates to better functional outcomes and quality of life.

Many randomized, controlled trials (RCTs) have evaluated the benefits of bipolar hemiarthroplasty (HA) vs unipolar HA, but there is inconsistency across the studies regarding outcomes.4–6 The aim of the current study was to evaluate the clinical outcomes of bipolar vs unipolar HA, including the rates of dislocation, reoperation, acetabular erosion, mortality, and general complications, as well as the Harris Hip Score.

Materials and Methods

Inclusion Criteria

All RCTs comparing bipolar HA with unipolar HA for the treatment of femoral neck fractures were considered for this review. Quasirandomized trials, cohort studies, retrospective studies, and other nonrandomized, comparative studies were excluded. All patients were adults and were randomized into 2 groups: bipolar HA and unipolar HA. All patient parameters, including number, age, and body mass index (BMI), were comparable between groups.

Exclusion Criteria

The following criteria were used to exclude studies from the analysis: (1) studies in which the surgical technique (whether bipolar or unipolar HA) could not be defined; and (2) studies in which the outcome of comparison of both techniques was not reported or it was not possible to calculate this from the published results.

Treatments of Interest

Bipolar HA and unipolar HA were compared by way of the following factors: dislocation rate, reoperation rate, acetabular erosion rate, mortality rate, general complication rate, and Harris Hip Score. General complications included pneumonia, pressure ulcer, myocardial infarction, pulmonary embolism, and deep venous thrombosis.

Search Technique and Data Extraction

An Internet-based search was undertaken using PubMed and the Cochrane Register of Controlled Trials database using the keywords hemiarthroplasty and neck of femur fracture to identify relevant studies published in English between 1966 and April 2014. Articles that had relevant titles were retrieved and assessed for inclusion. Eight articles fulfilled the criteria and were selected.4,6–12 Data were collected by 2 independent researchers (F.Y., X.Z.) who screened titles, abstracts, and keywords; differences were resolved by discussion. The studies were assessed in terms of blinding, allocation concealment, follow-up coverage, and quality level (according to whether allocation concealment was adequate [A], unclear [B], inadequate [C], or not used to assess the study quality [D]).

Statistical Analysis

The relative risk (RR) was calculated in each study for dichotomous outcomes, and the weighted mean difference (WMD) was calculated for continuous outcomes using Review Manager version 5.0 statistical software (Cochrane, Oxford, United Kingdom). The RR and WMD adopted a 95% confidence interval (CI). Heterogeneity was tested using the chi-square test and the I2 test. A significance level of P<.10 for the chi-square test was interpreted as evidence of heterogeneity. The I2 test was used to estimate the total variation among the studies. When no statistical evidence of heterogeneity existed, a fixed-effects model was adopted. Otherwise, a random-effects model was chosen. The authors did not include the possibility of publishing bias due to the small number of studies included.

Results

Using the inclusion and exclusion criteria, 8 studies comparing unipolar HA with bipolar HA were identified.4,6–12 The number of fractures in each study ranged from 48 to 261. A total of 1100 fractures occurred; 548 fractures were treated with unipolar HA, and 552 were treated with bipolar HA. Most studies evaluated the rates of dislocation, reoperation, acetabular erosion, mortality, and general complications, as well as the postoperative Harris Hip Score.

Four studies7,8,10,12 were level A quality, and 4 studies4,6,9,11 were level B quality because the randomization or allocation concealment was unclear according to the evaluation criteria (Tables 12).

Studies Included in the Meta-analysis

Table 1:

Studies Included in the Meta-analysis

Methodological Quality of Included Studies

Table 2:

Methodological Quality of Included Studies

Dislocation

Dislocation occurred in 9 of 521 fractures managed with unipolar HA and 8 of 528 fractures managed with the bipolar HA. Heterogeneity tests indicated no statistical evidence of heterogeneity (chi-square=1.01; P=.99; I2=0%). The data were pooled using a fixed-effects model and indicated that there was no difference in dislocation rate between unipolar HA and bipolar HA (RR=1.02; 95% CI, 0.47 to 3.07; P=.71) (Figure 1). Sensitivity analysis for dislocation rate did not identify significant differences in the relative risk of heterogeneity using random- and fixed-effects models (Figure 2).

Comparison of dislocation rate between unipolar and bipolar hemiarthroplasty. Each relative risk and its 95% confidence interval are plotted as a square and a line. A large black diamond reflects pooled evidence. The black vertical line represents a relative risk of 1.0.

Figure 1:

Comparison of dislocation rate between unipolar and bipolar hemiarthroplasty. Each relative risk and its 95% confidence interval are plotted as a square and a line. A large black diamond reflects pooled evidence. The black vertical line represents a relative risk of 1.0.

Sensitivity analysis for dislocation.

Figure 2:

Sensitivity analysis for dislocation.

Reoperation

Reoperation occurred in 13 of 374 fractures managed with unipolar HA and 20 of 377 fractures managed with bipolar HA. Heterogeneity tests indicated no statistical evidence of heterogeneity (chi-square=3.20; P=.53; I2=0%). The data were pooled using a fixed-effects model and indicated that there was no difference in reoperation rate between unipolar HA and bipolar HA (RR=0.64; 95% CI, 0.33 to 1.26; P=.19) (Figure 3).

Comparison of reoperation rate between unipolar and bipolar hemiarthroplasty. Each relative risk and its 95% confidence interval are plotted as a square and a line. A large black diamond reflects pooled evidence. The black vertical line represents a relative risk of 1.0.

Figure 3:

Comparison of reoperation rate between unipolar and bipolar hemiarthroplasty. Each relative risk and its 95% confidence interval are plotted as a square and a line. A large black diamond reflects pooled evidence. The black vertical line represents a relative risk of 1.0.

Acetabular Erosion

Acetabular erosion occurred in 12 of 284 fractures managed with unipolar HA and 4 of 268 fractures managed with bipolar HA. Heterogeneity tests indicated no statistical evidence of heterogeneity (chi-square=1.27; P=.74; I2=0%). The data were pooled using a fixed-effects model and indicated that there was no difference in acetabular erosion rate between unipolar HA and bipolar HA (RR=2.29; 95% CI, 0.85 to 6.12; P=.10) (Figure 4).

Comparison of acetabular erosion rate between unipolar and bipolar hemiarthroplasty. Each relative risk and its 95% confidence interval are plotted as a square and a line. A large black diamond reflects pooled evidence. The black vertical line represents a relative risk of 1.0.

Figure 4:

Comparison of acetabular erosion rate between unipolar and bipolar hemiarthroplasty. Each relative risk and its 95% confidence interval are plotted as a square and a line. A large black diamond reflects pooled evidence. The black vertical line represents a relative risk of 1.0.

Mortality

Four articles comprising 603 patients provided mortality data within 24 months. Among the 309 patients managed using unipolar HA, 65 deaths occurred, and among the 294 patients managed using bipolar HA, 71 deaths occurred. Heterogeneity tests indicated no statistical evidence of heterogeneity (chi-square=0.72; P=.87; I2=0%). The data were pooled using a fixed-effects model and indicated that there was no difference in mortality rate between unipolar HA and bipolar HA (RR=0.85; 95% CI, 0.63 to 1.13; P=.26) (Figure 5).

Comparison of mortality rate between unipolar and bipolar hemiarthroplasty. Each relative risk and its 95% confidence interval are plotted as a square and a line. A large black diamond reflects pooled evidence. The black vertical line represents a relative risk of 1.0.

Figure 5:

Comparison of mortality rate between unipolar and bipolar hemiarthroplasty. Each relative risk and its 95% confidence interval are plotted as a square and a line. A large black diamond reflects pooled evidence. The black vertical line represents a relative risk of 1.0.

General Complication

General complications occurred in 41 of 248 fractures managed with unipolar HA and 39 of 248 fractures managed with bipolar HA. Heterogeneity tests indicated no statistical evidence of heterogeneity (chi-square=1.89; P=.39; I2=0%). The data were pooled using a fixed-effects model and indicated that there was no difference in general complication rate between unipolar HA and bipolar HA (RR=1.05; 95% CI, 0.70 to 1.56; P=.10) (Figure 6).

Comparison of general complication rate between unipolar and bipolar hemiarthroplasty. Each relative risk and its 95% confidence interval are plotted as a square and a line. A large black diamond reflects pooled evidence. The black vertical line represents a relative risk of 1.0.

Figure 6:

Comparison of general complication rate between unipolar and bipolar hemiarthroplasty. Each relative risk and its 95% confidence interval are plotted as a square and a line. A large black diamond reflects pooled evidence. The black vertical line represents a relative risk of 1.0.

Harris Hip Score

No difference was found in postoperative Harris Hip Scores between patients undergoing unipolar HA and bipolar HA (WMD=−1.32; 95% CI, −3.29 to 0.65; P=.19). Heterogeneity tests indicated no statistical evidence of heterogeneity (chi-square=0.99; P=.61; I2=0%). Data were pooled using a fixed-effects model (Figure 7).

Comparison of postoperative Harris Hip Score between unipolar and bipolar hemiarthroplasty. Each relative risk and its 95% confidence interval are plotted as a square and a line. A large black diamond reflects pooled evidence. The black vertical line represents a relative risk of 1.0.

Figure 7:

Comparison of postoperative Harris Hip Score between unipolar and bipolar hemiarthroplasty. Each relative risk and its 95% confidence interval are plotted as a square and a line. A large black diamond reflects pooled evidence. The black vertical line represents a relative risk of 1.0.

Discussion

The geriatric population is increasing worldwide, and femoral neck fractures have become a major public health concern. Contemporary evidence from RCTs is compelling and indicates that the treatment of choice for a displaced fracture of the femoral neck in an elderly patient is arthroplasty. In the majority of elderly and frail patients, a cemented HA is the choice for most surgeons.13 Hemiarthroplasty is a procedure in which the head and neck of the femur are replaced with a prosthesis but the acetabulum is not modified. When using an HA, there are 2 types of articulations of the prosthesis and the patient's acetabulum: unipolar or bipolar. Whereas the unipolar head has a single articulation between the prosthesis and the acetabulum, the bipolar head offers a second articulation between an inner smaller head and the polyethylene liner of the larger outer head. The choice of prosthesis in HA is controversial. The theoretical advantage of the bipolar prosthesis is the motion at its inner bearing in addition to the prosthesis-acetabulum interface.14 This should decrease the amount of acetabular erosion evidenced radiologically and reduce pain clinically. Nevertheless, studies have shown that the inner bearing loses mobility over time and that the bipolar prosthesis behaves similarly to the unipolar prosthesis.15,16

The results of the current study demonstrated no differences regarding hip complications, such as dislocation (RR=1.02; 95% CI, 0.47 to 3.07; P=.71) and acetabular erosion (RR=2.29; 95% CI, 0.85 to 6.12; P=.10), in elderly patients with a displaced fracture of the femoral neck randomized to either a unipolar HA or a bipolar HA. A study by Dalldorf et al17 comparing the histologic features of acetabular specimens of patients undergoing revision HA against age-matched subjects suggested that acetabular wear correlated directly with the amount of time the implant remained in the hip rather than the type of implant used. It has also been suggested in the literature that acetabular wear is more of an issue in younger, more active patients.18 Tsukamoto et al19 conducted cadaver motion studies of bipolar implants and found that in stems loaded with less than 10 kg, motion occurred at both bearings. If greater than 20 kg was applied, the outer bearing was the primary site of articulation. Only when the acetabular cartilage was removed did motion occur at the inner bearing. Leonardsson et al20 found the most common reasons for HA reoperation and revision were implant dislocation and infection, accounting for three-quarters of patients, and there was no difference (RR=0.64; 95% CI, 0.33 to 1.26; P=.19) in the rate of reoperation between the 2 groups.

The current meta-analysis failed to demonstrate any differences in the rates of mortality and general complications between the 2 groups. The literature shows that increased age,21 high American Society of Anesthesiologists score,22 and delayed surgery23 are correlated with increased mortality and complications.

In theory, the bipolar prosthesis design with an additional inner articulation can entail a better range of motion and better functional outcome. However, the current study found no functional differences (Harris Hip Score) between unipolar and bipolar HA (WMD=−1.32; 95% CI, −3.29 to 0.65; P=.19). de los Santos et al24 reported no significant differences in function between patients with unipolar vs bipolar prostheses, but patients in the latter group presented lower pain scores, more quickly regained the ability to walk, and used fewer external supports. Perhaps the fact that patients receiving a bipolar HA were younger and presented a better functional status before fracture was also responsible for this difference.24

Meta-analysis of RCTs is generally considered to provide the strongest evidence of clinical interventions and has more advantages than observational studies and single randomized trials. Nevertheless, some possible limitations to this study should be acknowledged. First, although every effort was made to ensure the results were accurate, not all related randomized trials were included because of publication bias, which may have excluded obvious outcome differences of the 2 treatment methods, and selection bias, which may have excluded selective studies that preferred some kind of treatment. Strict searches in the library and of included bibliographies were conducted to reduce bias. Second, the problem is study heterogeneity, both in the nature of the studies themselves and in the statistical heterogeneity of individual relative risks. Concerning the latter, there was no apparent heterogeneity. There were differences in the protocols of the studies identified. For example, although all studies included elderly patients, there were differences in age ranges (Table 1) in the studies included. It is possible that there may be effect modification by age, but the authors could not determine this from the data available. Third, the clinical outcomes of cemented and uncemented unipolar HA or bipolar HA differed, and a previous Cochrane review suggested there was good evidence that cementing the prostheses in place would reduce postoperative pain and lead to better mobility25; however, the authors did not perform subgroup analyses according to cemented or uncemented status owing to the limited studies reported in the original reports.

Conclusion

The authors found that both unipolar and bipolar HA have satisfying results for displaced femoral neck fractures. The theoretical advantages of bipolar HA have not been supported by clinical studies, and the equivalent functional outcomes with the lower initial cost of unipolar HA should be considered.

References

  1. Giannoudis PV, Kontakis G, Christoforakis Z, Akula M, Tosounidis T, Koutras C. Management, complications and clinical results of femoral head fractures. Injury. 2009; 40(12):1245–1251. doi:10.1016/j.injury.2009.10.024 [CrossRef]
  2. Sterling RS. Gender and race/ethnicity differences in hip fracture incidence, morbidity, mortality, and function. Clin Orthop Relat Res. 2011; 469(7):1913–1918. doi:10.1007/s11999-010-1736-3 [CrossRef]
  3. Lowe JA, Crist BD, Bhandari M, Ferguson TA. Optimal treatment of femoral neck fractures according to patient's physiologic age: an evidence-based review. Orthop Clin North Am. 2010; 41(2):157–166. doi:10.1016/j.ocl.2010.01.001 [CrossRef]
  4. Inngul C, Hedbeck CJ, Blomfeldt R, Lapidus G, Ponzer S, Enocson A. Unipolar hemiarthroplasty versus bipolar hemiarthroplasty in patients with displaced femoral-neck fractures: a four-year follow-up of a randomised controlled trial. Int Orthop. 2013; 37(12):2457–2464. doi:10.1007/s00264-013-2117-9 [CrossRef]
  5. Ong BC, Maurer SG, Aharonoff GB, Zuckerman JD, Koval KJ. Unipolar versus bipolar hemiarthroplasty: functional outcome after femoral neck fracture at a minimum of 36 months of follow-up. J Orthop Trauma. 2002; 16(5):317–322. doi:10.1097/00005131-200205000-00005 [CrossRef]
  6. Calder SJ, Anderson GH, Jagger C, Harper WM, Gregg PJ. Unipolar or bipolar prosthesis for displaced intracapsular hip fracture in octogenarians: a randomised prospective study. J Bone Joint Surg Br. 1996; 78(3):391–394.
  7. Cornell CN, Levine D, O'Doherty J, Lyden J. Unipolar versus bipolar hemiarthroplasty for the treatment of femoral-neck fractures in the elderly. Clin Orthop Relat Res. 1998; 348:67–71. doi:10.1097/00003086-199803000-00012 [CrossRef]
  8. Davison JN, Calder SJ, Anderson GH, et al. Treatment for displaced intracapsular fracture of the proximal femur: a prospective, randomised trial in patients aged 65 to 79 years. J Bone Joint Surg Br. 2001; 83(2):206–212. doi:10.1302/0301-620X.83B2.11128 [CrossRef]
  9. Malhotra R, Arya R, Bhan S. Bipolar hemiarthroplasty in femoral-neck fractures. Arch Orthop Trauma Surg. 1995; 114(2):79–82. doi:10.1007/BF00422830 [CrossRef]
  10. Raia FJ, Chapman CB, Herrera MF, Schweppe MW, Michelsen CB, Rosenwasser MP. Unipolar or bipolar hemiarthroplasty for femoral-neck fractures in the elderly?Clin Orthop Relat Res. 2003; 414:259–265. doi:10.1097/01.blo.0000081938.75404.09 [CrossRef]
  11. Stoffel KK, Nivbrant B, Headford J, Nicholls RL, Yates PJ. Does a bipolar hemiprosthesis offer advantages for elderly patients with neck of femur fracture? A clinical trial with 261 patients. ANZ J Surg. 2013; 83(4):249–254. doi:10.1111/ans.12048 [CrossRef]
  12. Jeffcote B, Li MG, Barnet-Moorcroft A, Wood D, Nivbrant B. Roentgen stereophotogrammetric analysis and clinical assessment of unipolar versus bipolar hemiarthroplasty for subcapital femur fracture: a randomized prospective study. ANZ J Surg. 2010; 80(4):242–246. doi:10.1111/j.1445-2197.2009.05040.x [CrossRef]
  13. Bhandari M, Devereaux PJ, Tornetta P III, et al. Operative management of displaced femoral neck fractures in elderly patients: an international survey. J Bone Joint Surg Am. 2005; 87(9):2122–2130. doi:10.2106/JBJS.E.00535 [CrossRef]
  14. Bateman JE. The classic. Single-assembly total hip prosthesis preliminary report: 1974. Clin Orthop Relat Res. 2005; 441:16–18. doi:10.1097/01.blo.0000194930.63766.7a [CrossRef]
  15. Chen SC, Badrinath K, Pell LH, Mitchell K. The movements of the components of the Hastings bipolar prosthesis: a radiographic study in 65 patients. J Bone Joint Surg Br. 1989; 71(2):186–188.
  16. Verberne GH. A femoral head prosthesis with a built-in joint: a radiological study of the movements of the two components. J Bone Joint Surg Br. 1983; 65(5):544–547.
  17. Dalldorf PG, Banas MP, Hicks DG, Pellegrini VD Jr, . Rate of degeneration of human acetabular cartilage after hemiarthroplasty. J Bone Joint Surg Am. 1995; 77(6):877–882.
  18. Ito H, Matsuno T, Kaneda K. Bipolar hemiarthroplasty for osteonecrosis of the femoral head: a 7- to 18-year follow-up. Clin Orthop Relat Res. 2000; 374:201–211. doi:10.1097/00003086-200005000-00019 [CrossRef]
  19. Tsukamoto Y, Mabuchi K, Futami T, Kubotera D. Motion of the bipolar hip prosthesis components. Acta Orthop Scand. 1992; 63(6):648–652.
  20. Leonardsson O, Kärrholm J, Åkesson K, Garellick G, Rogmark C. Higher risk of reoperation for bipolar and uncemented hemiarthroplasty. Acta Orthop. 2012; 83(5):459–466. doi:10.3109/17453674.2012.727076 [CrossRef]
  21. Aharonoff GB, Koval KJ, Skovron ML, Zuckerman JD. Hip fractures in the elderly: predictors of one year mortality. J Orthop Trauma. 1997; 11(3):162–165. doi:10.1097/00005131-199704000-00004 [CrossRef]
  22. Michel JP, Klopfenstein C, Hoffmeyer P, Stern R, Grab B. Hip fracture surgery: is the preoperative American Society of Anesthesiologists (ASA) score a predictor of functional outcome?Aging Clin Exp Res. 2002; 14(5):389–394. doi:10.1007/BF03324467 [CrossRef]
  23. Sircar P, Godkar D, Mahgerefteh S, Chambers K, Niranjan S, Cucco R. Morbidity and mortality among patients with hip fractures surgically repaired within and after 48 hours. Am J Ther. 2007; 14(6):508–513. doi:10.1097/01.pap.0000249906.08602.a6 [CrossRef]
  24. de los Santos R, Cordero-Ampuero J, Rodriguez-Salvanés F, González R. Comparison of radiological acetabular erosion between hemiarthroplasties: cemented Thompson unipolar vs. uncemented HAP Furlong bipolar. Eur Orthop Traumatol. 2012; 3(2):115–120. doi:10.1007/s12570-012-0106-x [CrossRef]
  25. Parker MJ, Gurusamy KS, Azegami S. Arthroplasties (with and without bone cement) for proximal femoral fractures in adults. Cochrane Database Syst Rev. 2010; 6:CD001706.

Studies Included in the Meta-analysis

Study Age, Mean±SD (Range), y, Unipolar/Bipolar Men No. of Fractures, Unipolar/Bipolar Country Follow-up, mo
Inngul et al4 87.4 (80–100)/85.5 (80–96) 24.1% 60/60 Sweden 48
Calder et al6 85 (82–88)/85 (82–88) 14% 132/118 UK 24
Cornell et al7 77.6±10/78.0±8 25% 15/33 US 6
Davison et al8 76 (72–77)/75 (71–78) 23.5% 90/97 UK 60
Malhotra et al9 68/65 55.6% 36/32 India 26
Raia et al10 81.8 (65–101)/82.4 (65–95) 27.8% 60/55 US 24
Stoffel et al11 81.9±8.8/82.9±9.7 28% 128/133 Australia 12
Jeffcote et al12 81.4/80.1 23.5% 27/24 Australia 24

Methodological Quality of Included Studies

Study Baseline Randomization Allocation Concealment Blinding Lost to Follow-up Quality Level

Age Sex
Inngul et al4 Comparable Comparable Inadequate Clear Unclear Yes B
Calder et al6 Comparable Comparable Adequate Clear Unclear Yes B
Cornell et al7 Comparable Comparable Adequate Clear Clear Yes A
Davison et al8 Comparable Comparable Adequate Clear Clear Yes A
Malhotra et al9 Comparable Comparable Inadequate Unclear Unclear Not reported B
Raia et al10 Comparable Comparable Adequate Clear Clear Yes A
Stoffel et al11 Comparable Comparable Inadequate Unclear Clear Yes B
Jeffcote et al12 Comparable Comparable Adequate Clear Clear Yes A

Authors

The authors are from the Department of Orthopedic Surgery, Zhangjiagang First People's Hospital, Zhangjiagang, Jiangsu, China.

The material presented in any Keck School of Medicine of USC continuing education activity does not necessarily reflect the views and opinions of Orthopedics or Keck School of Medicine of USC. Neither Orthopedics nor Keck School of Medicine of USC nor the authors endorse or recommend any techniques, commercial products, or manufacturers. The authors may discuss the use of materials and/or products that have not yet been approved by the US Food and Drug Administration. All readers and continuing education participants should verify all information before treating patients or using any product.

Correspondence should be addressed to: Xingxiang Zhang, MD, Department of Orthopedic Surgery, Zhangjiagang First People's Hospital, Zhangjiagang, Jiangsu 215600, China ( zhangxx7290@126.com).

Received: June 01, 2014
Accepted: November 17, 2014

10.3928/01477447-20151016-08

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