Management and outcome of the dislocated hip hemiarthroplasty

Does delay from injury to surgery increase the risk of dislocation of a hip hemiarthroplasty?

Dislocation of a hip hemiarthroplasty used to treat a hip fracture is a serious complication. The aim of this study was to identify whether a delay in the time from fracture to surgery causes an increase in the rate of post-operative hip dislocation. From a single center, data from intracapsular neck of femur patients treated with hip hemiarthroplasty was collected between October 1986 to August 2021. The time from both fall to surgery and admission to surgery was recorded. Surviving patients were followed up for one year. The overall dislocation rate was 51 out of 4155 patients (1.2%). The 3019 patients who had surgery within two days of the injury had a lowest dislocation rate (29 dislocations, 0.96%). For the 197 patients with no history of a fall, there were 5 (2.5%) dislocations (p=0.036, 95% confidence interval of difference 0.15 to 0.97 for comparison with surgery within two days). For the 399 patients with a delay of more than four days from injury till surgery, there were nine dislocations (2.3%) (p=0.045, 95% confidence intervals of difference 0.20 to 0.89 for comparison with surgery within two days). This study demonstrates an increase in the risk of dislocation for those patients with no history of a fall and those with a delay of more than four days from injury to surgery.

Patients undergoing hip hemiarthroplasty who require early return to theatre have early increased mortality and worse functional outcomes at short term follow-up

BACKGROUND

Re-operation following hip hemiarthroplasty is potentially devastating due to a frail, co-morbid surgical cohort. We aimed to assess the outcomes of patients who required early return to theatre (RTT) within 30 days of index operation in a high-volume hip fracture unit.

METHODS

A retrospective review of a prospectively maintained database was undertaken. All hip hemiarthroplasties performed between 1st January 2010 and 31st December 2019 was included. Demographic details, complications including reason for return to theatre, length of stay, discharge destination, functional outcome and mortality were collected and reviewed.

RESULTS

4340 hip hemiarthroplasty procedures were performed, of which 64 patients (1.47%) required early RTT within 30 days of index procedure and 4276 patients did not require early-RTT. The most common reasons for RTT were infection (n = 47) and dislocation (n = 15). There were no cases of peri‑prosthetic fracture requiring RTT within 30 days. Patients requiring early RTT had a significantly increased rate of mortality within 120 days; 32.8% (21 of the 64 patients) versus 13.6% (580 out of the 4276) not requiring early RTT (p < 0.001). The median length of acute inpatient admission for patients who required early RTT was significantly longer at 31 days (range 6-185 days) compared to 10 days (range 3-171 days, p < 0.001) for those without early RTT. Early RTT was associated with a poorer functional mobility outcome at 120 days post-operatively, with a significantly greater reduction in Barthel score compared to the non-RTT cohort (p < 0.05).

CONCLUSION

Patients requiring early RTT following hip hemiarthroplasty had a significantly increased length of stay, mortality and worse functional outcome compared to patients who did not require early RTT within 30 days.

The outcomes of constrained total hip arthroplasty for recurrent dislocation of hip hemiarthroplasty

INTRODUCTION

The incidence of hemiarthroplasty dislocation for fracture neck of femurs ranges between 1 and 15% and the one-year mortality is 49- 70%. Revision of hemiarthroplasty to total hip replacement using a constrained liner has shown to improve the morbidity and mortality rates. The aim of the study was to assess whether conversion of dislocated hemiarthroplasty to total hip replacement improve functional and one year mortality.

METHODS

A retrospective analysis of the number of patients who had recurrent dislocations of hemiarthroplasty for fracture neck of femurs were carried out. The data were obtained from NHFD (National Hip Fracture Database) and internal hospital computer systems (Medway, Theatre notes and PACS) between Dec 2008 and Dec 2020. Patient demographics including age, sex, Abbreviated Mental Test Score (AMTS), functional assessment, mortality at one and two years were documented. The risk factors which led to dislocations such as Parkinsons disease, Cerebrovascular accidents, Musculo-neuropathies and Alzheimer`s disease was also noted.

RESULTS

A total of 3994 patients were admitted during the study period of which 1735 (43.4%) patients had hemiarthroplasty. Fifty-six (3.23%) patients had dislocation of hemiarthroplasty. The mean age was 81.4 years (range - 61 to 95). There were 40 (71.4%) females and 16 males (28.6%). The average AMTS score was 5.3. All 56 patients had closed manipulative reduction under anaesthesia within in 12 h of admission. Thirty-one patients (55.4%) went on to have recurrent dislocations of which 18 patients (58.4%) had total hip replacement using captive cup, 6 patients (19.4%) had open reduction,3 patients (9.7%) had excision arthroplasty procedure and four patients (12.5%) had no intervention, Eighteen patients who had total hip replacement with constrained captive for followed up to a minimum of two years (range2- 12 years). There were no intraoperative complications, dislocation or periprosthetic fractures in the follow up period. There was no mortality at the end of two years of follow up in this group, two-year mortality for the patients with alternative management for dislocated hemiarthroplasty was 76.67.

CONCLUSION

Treatment of recurrent hemiarthroplasty dislocation by revising to a total hip replacement with a constrained liner gives good functional and mortality outcomes.

Surgical Approach and Dislocation Risk After Hemiarthroplasty in Geriatric Patients With Femoral Neck Fracture With and Without Cognitive Impairments-Does Cognitive Impairment Influence Dislocation Risk?

OBJECTIVES

To determine whether there is an association between surgical approach and dislocation risk in patients with cognitive impairment compared with those without cognitive impairment treated with hemiarthroplasty for femoral neck fracture.

DESIGN

Retrospective study.

SETTING

Large, multicenter health system.

PATIENTS/PARTICIPANTS

One thousand four hundred eighty-one patients who underwent hemiarthroplasty for femoral neck fractures. 828 hips met inclusion criteria, 290 (35.0%) were cognitively impaired, and 538 (65.0%) were cognitively intact.

INTERVENTION

Hemiarthroplasty.

MAIN OUTCOME MEASURE

Prosthetic hip dislocation.

RESULTS

The overall dislocation rate was 2.1% (17 of 828), 3.4% (10 of 290) in the cognitively impaired group, and 1.3% (7 of 538) in the cognitively intact group with a median time to dislocation of 20.5 days (range 2-326 days), 24.5 days (range 3-326 days), and 19.0 days (range 2-36 days), respectively. In the entire cohort, there were no dislocations (0 of 58) with the direct anterior approach (DA); 1.1% (6 of 553) and 5.1% (11 of 217) dislocated with the modified Hardinge (MH) and posterior approaches (PA), respectively. In the cognitively impaired group, there were no dislocations with the DA (0 of 19); 1.5% (3 of 202) and 10.1% (7 of 69) dislocated with the MH and PA, respectively. In the cognitively intact group, there were no dislocations (0 of 39) with the DA; 0.85% (3 of 351) and 2.7% (4 of 148) dislocated with the MH and PA, respectively. There were statistically significant associations between surgical approach and dislocation in the entire cohort and the cognitively impaired group when comparing the MH and PA groups. This was not observed in the cognitively intact group. Patients who dislocated had 3.2 times (95% CI 1.2, 8.7) ( P = 0.0226) the hazard of death compared with patients who did not dislocate. Dislocation effectively increased the risk of death by 221% (HR 3.2 95% CI 1.2, 8.7) ( P = 0.0226).

CONCLUSIONS

In this patient population, the PA has a higher dislocation rate than other approaches and has an especially high rate of dislocation when the patients were cognitively impaired. The authors of this study suggest careful consideration of surgical approach when treating these injuries.

LEVEL OF EVIDENCE

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

Complications of Hip Hemiarthroplasty

Hip hemiarthroplasty is a commonly performed orthopedic surgery, used to treat proximal femur fractures in the elderly population. Although hip hemiarthroplasty is frequently successful in addressing these injuries, complications can occur. Commonly seen complications include dislocation, periprosthetic fracture, acetabular erosion, and leg-length inequality. Less frequently seen complications include neurovascular injury and capsular interposition. This article presents a comprehensive review of the complications associated with the management of hip hemiarthroplasty. [Orthopedics. 2023;46(4):e199-e209.].

Comparison of Dislocation and Outcome Between Piriformis-Sparing and Conventional Posterior Approach After Bipolar Hemiarthroplasty for Femoral Neck Fracture in Patients Over 60 Years

BACKGROUND

Hemiarthroplasty is a treatment option for femoral neck fractures in patients aged more than 60 years and postoperative dislocation after a posterior approach is not uncommon. The piriformis tendon is one of the structures providing posterior hip stability. However, evidence of piriformis-sparing approach in hemiarthroplasty is unclear regarding a reduced dislocation rate.

METHODS

Between January 2017 and December 2019, 321 patients underwent a posterior approach in consecutive cohorts for a hemiarthroplasty for femoral neck fractures with the minimum 24 months follow-up time (24-60 months). There were two cohorts: (1) 129 underwent the conventional posterior (CP) approach and (2) 192 underwent the piriformis-sparing (PS) approach. The differences in dislocation rate, postoperative Harris Hip Society at 1 and 2 years and other surgical complications were compared in both groups.

RESULTS

There were 6 dislocations of 129 (4.7%) underwent the CP approach and 0 dislocation from 192 underwent the PS approach that had posterior hip dislocations (P = .004). In addition, the CP group had a significantly higher mortality rate (14.7% versus 7.3%, P = .031) and lower functional outcomes as assessed by mean Harris Hip Scores at 1 year (73 versus 78, P = .005) and 2 years postoperatively (73 versus 80, P < .001) relative to the PS group.

CONCLUSION

PS hemiarthroplasty was associated with a lower dislocation and mortality rate. Moreover, this approach gained a superior early to the mid-term functional outcome than the conventional posterior approach in elderly femoral neck fractures.

LEVEL OF EVIDENCE

II, prospective cohort study.

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.

Should we employ preoperative templating in hip hemiarthroplasty after femoral neck fracture? A nested case-control study

INTRODUCTION

Dislocation following hip hemiarthroplasty is a serious complication. It remains unclear if acetabular morphology is associated with a higher risk of dislocation. The aim of our study was to investigate whether there are differences in hip morphology radiological parameters between patients who have suffered a dislocation episode, and those who have not suffered a dislocation.

MATERIAL AND METHODS

Between January 2015 and December 2018, a nested case-control study was performed. From 707 patients who underwent hip hemiarthroplasty because of femoral neck fracture, 50 patients (50 hips) suffered an episode of dislocation. They were randomly matched with 94 patients (100 hips) without dislocation (ratio 1:2). Clinical data regarding demographics, medical comorbidities and surgical and radiological parameters were studied.

RESULTS

Statistically significantly smaller lateral centre-edge angle (LCEA) and femoral offset (FO) and greater Tönnis angle were found in the dislocation group. No differences in acetabular angle were seen. Neurological impairment prevalence was statistically significantly higher in patients who suffered a dislocation (60% vs. 44%, p = 0.011).

CONCLUSIONS

The current study suggests that a smaller LCEA and FO, a greater TA, and neurological impairment could be related to a higher risk of hip hemiarthroplasty dislocation after femoral neck fracture in the elderly. We consider that preoperative templating could be helpful in identifying abnormal parameters and carefully planning surgery could lead to changes in treatment strategy, such as choosing a dual-mobility total hip arthroplasty.

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.

Dislocation of hemiarthroplasty after hip fracture is common and the risk is increased with posterior approach: result from a national cohort of 25,678 individuals in the Swedish Hip Arthroplasty Register

Background and purpose - Reported revision rates due to dislocation after hemiarthroplasty span a wide range. Dislocations treated with closed reduction are rarely reported despite the fact that they can be expected to constitute most of the dislocations that occur. We aimed to describe the total dislocation rate on the national level, and to identify risk factors for dislocation.Patients and methods - We co-processed a national cohort of 25,678 patients in the Swedish Hip Arthroplasty Register, with the National Patient Register (NPR) and Statistics Sweden. Dislocation was defined as the occurrence of any ICD-10 or procedural code related to hip dislocation recorded in the NPR, with a minimum of 1-year-follow-up. In theory, all early dislocations should thereby be traced, including those treated with closed reduction only.Results - 366/13,769 (2.7%) patients operated on with direct lateral approach dislocated, compared with 850/11,834 (7.2%) of those with posterior approach. Posterior approach was the strongest risk factor for dislocation (OR = 2.7; 95% CI 2.3-3.1), followed by dementia (OR = 1.3; CI 1.1-1.5). The older the patients, the lower the risk of dislocation (OR = 0.98 per year of age; CI 0.98-1.0). Neither bipolar design nor cementless stems influenced the risk.Interpretation - The choice of posterior approach and dementia was associated with an increased dislocation risk. When hips treated with closed reduction were identified, the frequency of dislocation with use of direct lateral and posterior approach more than doubled and tripled, respectively, compared with when only revisions due to dislocation are measured.

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.

30-day mortality after hip fracture surgery: Influence of postoperative factors

Purpose

The 30-day mortality rate after hip fracture surgery has been considered as an indirect indicator of the quality of care. The aim of this work is to analyse preoperative and postoperative factors potentially related to early 30-day mortality in patients over 65 undergoing hip fracture surgery.

Methods

Prospective cohort study including all consecutive primary hip fracture patients over 65 admitted to Trauma and Orthopaedics department from January 1, 2018 to December 31, 2019. Bed-ridden, non- surgically treated patients, and high energy trauma or tumoral aetiology fractures were excluded. A total of 943 patients were eligible (attrition rate: 2.1%). Follow-up included 30-days after discharge. We noted the 30-day mortality after hip fracture surgery, analysing 130 potentially related variables including biodemographic, fracture-related, preoperative, and postoperative clinical factors. Qualitative variables were assessed by χ², and quantitative variables by non-parametric tests. Odds ratio determined by binary logistic regression. We selected preventable candidate variables for multivariate risk assessment by logistic regression.

Results

A total of 923 patients were enrolled (mean age 86.22±6.8, 72.9% women). The 30-day mortality rate was 6.0%. We noted significant increased mortality on men (OR = 2.381[1.371–4.136], p = 0.002), ageing patients (OR_year = 1.073[1.025–1.122], p = 0.002), and longer time to surgery (OR_day = 1.183[1.039–1146], p<0.001), on other 20 preoperative clinical variables, like lymphopenia (lymphocyte count <10³/μl, OR = 1.842[1.063–3.191], p = 0.029), hypoalbuminemia (≤3.5g/dl, OR = 2.474[1.316–4.643], p = 0.005), and oral anticoagulant intake (OR = 2.499[1.415–4.415], p = 0.002), and on 25 postoperative clinical variables, like arrhythmia (OR = 13.937[6.263–31.017], p<0.001), respiratory insufficiency (OR = 7.002[3.947–12.419], p<0.001), hyperkalaemia (OR = 10.378[3.909–27.555], p<0.001), nutritional supply requirement (OR = 3.576[1.894–6.752], p = 0.021), or early arthroplasty dislocation (OR = 6.557[1.206–35.640], p = 0.029). We developed a predictive model for early mortality after hip fracture surgery based on postoperative factors with 96.0% sensitivity and 60.7% specificity (AUC = 0.863).

Conclusion

We revealed that not only preoperative, but also postoperative factors have a great impact after hip fracture surgery. The influence of post-operative factors on 30-day mortality has a logical basis, albeit so far they have not been identified or quantified before. Our results provide an advantageous picture of the 30-day mortality after hip fracture surgery.

Outcomes of total hip arthroplasty using dual mobility components in patients with a femoral neck fracture

AIMS

Dislocation is the most common indication for further surgery following total hip arthroplasty (THA) when undertaken in patients with a femoral neck fracture. This study aimed to assess the complication rates of THA with dual mobility components (THA-DMC) following a femoral neck fracture and to compare outcomes between THA-DMC, conventional THA, and hemiarthroplasty (HA).

METHODS

We performed a systematic review of all English language articles on THA-DMC published between 2010 and 2019 in the MEDLINE, EMBASE, and Cochrane databases. After the application of rigorous inclusion and exclusion criteria, 23 studies dealing with patients who underwent treatment for a femoral neck fracture using THA-DMC were analyzed for the rate of dislocation. Secondary outcomes included reoperation, periprosthetic fracture, infection, mortality, and functional outcome. The review included 7,189 patients with a mean age of 77.8 years (66.4 to 87.6) and a mean follow-up of 30.9 months (9.0 to 68.0).

RESULTS

THA-DMC was associated with a significantly lower dislocation rate compared with both THA (OR 0.26; 95% CI 0.08 to 0.79) and HA (odds ratio (OR) 0.27; 95% confidence interval (CI) 0.15 to 0.50). The rate of large articulations and of intraprosthetic dislocation was 1.5% (n = 105) and 0.04% (n = 3) respectively.

CONCLUSION

THA-DMC when used in patients with a femoral neck fracture is associated with a lower dislocation rate compared with conventional arthroplasty options. There was no increase in the rates of other complication when THA-DMC was used. Future cost analysis and prospective, comparative studies are required to assess the potential benefit of using THA-DMC in these patients. Cite this article: Bone Joint J 2020;102-B(7):811-821.

Thompson Hemiarthroplasty for Femoral Neck Fracture Is Associated With Increased Risk of Dislocation

BACKGROUND

This contemporaneous large multicenter retrospective study reflective of current practice, assesses the impact of patient factors, prosthesis selection, and implant features on the risk of dislocation after hip hemiarthroplasty for femoral neck fracture.

METHODS

Radiographic records for 4116 consecutive patients who underwent a hip hemiarthroplasty between January 1, 2009 and September 30, 2017 at 3 acute hospitals (including a regional major trauma center) for a neck of femur fracture were reviewed in conjunction with United Kingdom National Hip Fracture Database records.

RESULTS

In total, 4116 patients were eligible for inclusion in the study; 63 of 4116 (1.5%) dislocations were identified. Patient age, gender, preoperative abbreviated mental test score, postoperative abbreviated mental test score, and American Society of Anaesthesiologists grade were not found to be significant predictors of dislocation rates (P < .05). The Furlong prosthesis was the most commonly used implant (2280/4116, 55.4%) followed by the Exeter V40 + Unitrax head (1179/4116, 28.6%), other implants used during the study period were the monoblock Austin-Moore and Thompson implants. Hemiarthroplasty operations undertaken with the Thompson (24/273, 3.7%) were found to have significantly higher dislocation rates (P < .05). Cemented vs uncemented, variable vs fixed offset, and monoblock vs modular implant designs did not contribute to higher dislocation rates (P < .05). Surgeon seniority was also not a significant risk factor for subsequent dislocation (P < .05).

CONCLUSIONS

Thompson hip hemiarthroplasties are associated with higher dislocation rates when compared to a contemporaneous cohort of implant choices and considerations for their use should be made in conjunction with this major risk factor for the need for subsequent operations.

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

PURPOSE

This study aimed to investigate the anatomic risk factors associated with dislocation following bipolar hemiarthroplasty for the treatment of femoral neck fracture.

MATERIALS AND METHODS

We retrospectively reviewed 208 consecutive patients (133 women, 75 men) with femoral neck fractures who were treated with bipolar hemiarthroplasty between 2015 and 2018. A comparative analysis was performed between dislocation (n = 18) and non-dislocation (n = 190) groups in terms of patient demographics, surgical and pelvic morphologic factors, and clinical outcomes, including postoperative Harris and modified Harris hip scores. Independent risk factors affecting dislocation were also evaluated.

RESULTS

The mean follow-up period was 30.8 ± 2.0 (range, 12-48) months. The mean age was 79.2 ± 7.4 (range, 71-94) years. The dislocation rate was 8.6% (18/208), and the mean dislocation time after operation was 2.0 ± 1.1 (range, 1-4) months. Patient-related factors did not differ between the dislocated and non-dislocated groups. As regards dislocation, statistically significant difference was observed in surgical and pelvic morphologic factors, including femoral offset, residual femoral neck length, trochanter upper end and femoral head center distance, and height of the hip center of the operated side (p = 0.025, p = 0.013, p = 0.002, p = 0.008, respectively). Moreover, the femoral offset, height of the hip center, and femoral neck-shaft angle of the non-operated side are significantly different between the groups (p = 0.007, p = 0.001, p = 0.027, respectively). Decrease in the center edge (CE) angle, offset of prosthesis, and increase in femoral head extrusion index (FHEI) of the operated side and decrease in the height of the hip center of the non-operated side increased the risk of dislocation (p = 0.030, OR: 1,306; p = 0.041, OR: 8.15; p = 0.020, OR: 1.038; p = 0.010, OR: 2.02, respectively).

CONCLUSIONS

Pelvic morphologic features and surgical factors were found to affect dislocation. Patients with smaller OP, CE angle of the operated side, and higher FHEI and smaller height of the hip center of the non-operated side should be carefully monitored to decrease postoperative dislocation.