Dislocation of bipolar hip hemiarthroplasty through a postero-lateral approach for femoral neck fractures: A cohort study

Complete Joint Capsule-Preserving Posterior Approach in Hemiarthroplasty for Femoral Neck Fractures: A Technical Note and Learning Curve Analysis of Trainee Surgeons

Introduction: The posterior approach is widely used in hemiarthroplasty for femoral neck fractures. However, it has a high dislocation rate. In hemiarthroplasty, the joint capsule is commonly incised. This study aimed to identify a posterior surgical technique that completely preserves the joint capsule without incision and the use of special devices to remove the head, perform a trial, and place an implant. Further, the learning curves (LCs) of trainee surgeons and the associated complications of the posterior approach were evaluated via a retrospective case series. Materials and Methods: The LCs of trainee surgeons for surgical duration and volume of intraoperative blood loss in 60 cases were examined. The surgical procedures were conducted by three trainee surgeons for femoral neck fractures at a single institution between September 2018 and June 2021. Each surgeon consecutively performed 20 surgical procedures. Each surgeon's cases were divided into four groups, with 15 cases each: 1-5, group A; 6-10, group B; 11-15, group C; and 16-20, group D. Then, these cases were analyzed. Surgery-related complications, such as dislocation, femoral fractures, paralysis, and infection were investigated. Results: The four groups significantly differed in terms of the median operative duration (P = 0.017). In particular, there was a significant difference between groups A and C (P = 0.007) and between groups A and D (P = 0.006). There was an LC for the surgical duration. In 10 cases, the surgical duration was shorter. However, there was no significant difference in the volume of intraoperative blood loss among the four groups. None of the patients presented with dislocation or major complications. Discussion and Conclusions: An LC was observed for the surgical duration in 10 cases among the trainee surgeons. Moreover, the volume of intraoperative blood loss did not significantly increase during the LC period.

Comparison of conjoined tendon-preserving posterior approach and conventional posterolateral approach in hemiarthroplasty for femoral neck fracture in the elderly: A multicenter (TRON group) retrospective study

BACKGROUND

Femoral neck fractures (FNF) are one of the most common traumatic injuries in the elderly. The conjoined tendon-preserving posterior (CPP) approach was developed as a modification of the conventional posterolateral (PL) approach in hemiarthroplasty (HA) for displaced femoral neck fractures (FNF) to reduce postoperative dislocation. We hypothesized that the CPP approach would result in fewer dislocations and similar functional and radiographic outcomes compared to the PL approach.

PATIENTS AND METHODS

This was a retrospective multicenter (TRON group) study. We evaluated the rate of complications, and functional and radiographic outcomes for patients aged >65 years who underwent HA via the PL approach or the CPP approach from 2017 to 2019 and followed up for at least 24 months. To adjust for baseline differences between the groups, a propensity score-matching algorithm was used in a 1:1 ratio.

RESULTS

We identified 135 patients who underwent HA via the PL approach and 135 patients via the CPP approach. The mean follow-up period was 32.4 ± 14.0 months. The incidence of dislocation was 6 in 135 patients (4.4%) in the PL group and 0 in 135 patients (0%) in the CPP group, and there was significant difference (p = 0.04). Operation time was equivalent between the two groups (73.1 ± 30.4 vs. 71.8 ± 30.0 min; p = 0.72). The rate of varus insertion of stems in the PL group lower than that in the CPP group (19.3% vs. 33.3%; p = 0.01). Postoperative Parker's mobility score was similar between the two groups at 12 months follow-up (6.17 vs. 6.27; p = 0.81).

CONCLUSION

The CPP approach showed a significantly lower dislocation rate, similar functional outcome and more varus stem insertions compared with the PL approach in this retrospective study.

Comparison of surgical efficacy between direct anterior approach and posterolateral approach in the treatment of sarcopenia with femoral neck fractures

BACKGROUND

Femoral neck fracture (FNF) is a prevalent injury among the elderly, associated with significant morbidity and mortality. Total joint arthroplasty (TJA) has markedly enhanced the quality of life for many patients; however, the benefits of the direct anterior approach (DAA), which has gained popularity in recent years, remain a subject of debate. Sarcopenia frequently occurs in patients with FNF and is linked to adverse surgical outcomes. This study aims to compare the effects of the DAA and the posterolateral approach (PLA) on the efficacy of TJA surgery in patients with FNF who also present with sarcopenia.

METHODS

This study retrospectively analyzed the clinical data of patients with FNF who underwent total hip arthroplasty (THA) using either DAA or PLA from December 2019 to December 2022. A total of 141 individuals were included, comprising 52 in the DAA group and 89 in the PLA group. The cross-sectional area (cm²) of the musculature at the pedicle level of the 12th thoracic vertebra (T12) was measured using chest computed tomography (CT). The skeletal muscle index (SMI) was calculated by dividing the cross-sectional area of the muscle at the T12 pedicle level by the square of the individual's height. Sarcopenia was diagnosed when both grip strength and SMI values fell below the diagnostic cutoff. The study compared various factors, including age, gender, SMI, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, operation time, incision length, blood loss, blood transfusion, hemoglobin drop, albumin drop, postoperative time to ambulation, length of hospitalization, visual analogue scale (VAS) score, Harris score at one and six months post-surgery, complications, revision rate, one-year survival rate following surgery, and patient satisfaction.

RESULTS

There were no statistically significant differences between the two groups regarding gender, age, SMI, BMI, ASA, operation time, blood transfusion, VAS score six months post-surgery, revision rate, satisfaction, and survival rate (P > 0.05). The incision length, blood loss, hemoglobin drop, albumin drop, hospitalization duration, VAS score, and complication rate one month after the operation in the DAA group were all significantly lower than those in the PLA group (P < 0.001). Additionally, the Harris scores at one month and six days post-operation were superior in the DAA group compared to the PLA group (P < 0.001). Furthermore, the incidence of complications in the DAA group was lower than that in the PLA group (P = 0.041). Univariate and multivariate Cox regression analyses indicated that age was an independent risk factor for patients' mortality risk (95% CI: 1.064-1.479, P = 0.007).

CONCLUSION

DAA results in reduced surgical trauma, alleviates postoperative pain, decreases the incidence of complications, enhances the recovery of patients' mobility functions, shortens hospital stays, and is particularly suitable for FNF patients with sarcopenia.

Clinical and radiological factors related to dislocation in patients undergoing hip hemiarthroplasty for femoral neck fractures: A case-control study✰

INTRODUCTION

Dislocation rates are low in patients undergoing hemiarthoplasty (HA) for displaced femoral neck fractures (FNF); however, complications can be devastating. We hypothesize that patients sustaining HA dislocation have different comorbidities and surgical characteristics to those without.

MATERIALS AND METHODS

In this retrospective matched-control study, we identified 28 patients who sustained dislocation after HA. They were matched 1:2 based of sex and age to a cohort of patients undergoing HA without dislocation. We compared the pre-operative demographic and clinical data, surgical details, mortality and need for further revision or complications. The radiological analysis was performed by measuring the centre edge angle (CEA), acetabular index (AI), the femoral offset (FO), and the residual femoral neck (RFN) after surgery. The minimum follow-up for unrevised patients was one year (range, 1 to 4).

RESULTS

19 (67 %) out of 28 patients in the study group needed further surgery. The 1-year mortality rate was 44 % in the study group and 14 % in the control group (p < 0.001). A longer surgical delay (p < 0.001), dementia and neuromuscular disorders, a greater CEA (mean cases = 46º and controls = 38º; p < 0.001) and a shorter RFN (mean cases = 23.5 mm and controls = 28.4 mm; p = 0.04) was found in patients that suffered HA dislocation.

CONCLUSIONS

HA dislocation after FNF is a severe complication with high mortality rate and often require further surgery treatment. Dislocation was more frequent in patients with neuro-cognitive impairment, a longer surgical delay and a shorter femoral neck. Monitoring peri‑operative management and surgical technique may decrease the dislocation rate in this frail population.

LEVEL OF EVIDENCE

III.

Predicting Instability Risk Following Hemiarthroplasty for Femoral Neck Hip Fractures in Geriatric Patients

BACKGROUND

Although a rare complication, dislocation following hemiarthroplasty (HA) for a femoral neck hip fracture is associated with increased mortality, readmission, and possible revision surgery. To date many of the specific risk factors have been difficult to demonstrate. Patient factors, surgical factors, as well as morphological factors need to be assessed. Therefore, the purpose of this study was to elucidate the risk factors for dislocation of HA following femoral neck hip fractures in the geriatric population.

METHODS

This was a retrospective review of 270 patients who had hip fractures. Medical records between the years 2016 and 2022 informed binomial regression predictive models. The discriminative ability of variables in the final model and acetabular anteversion to predict dislocation was assessed with area under the curve (AUC) estimates.

RESULTS

Center edge angle (odds ratio 1.23), abduction angle (odds ratio 1.17), and depth width ratio (2.96e-11) were significant predictors of dislocation (P = .003, .028, and <.001, respectively). Center edge angle and depth width ratio (<44.1 ° and .298), respectively, were cut scores for risk. Dementia had a high discriminative of ability, as did men (AUC = 0.617, 0.558, respectively). Acetabular anteversion was not predictive of dislocation (P = .259) and theorized anteversion safe zones had poor discriminative ability with AUCs of 0.510 and 0.503, respectively.

CONCLUSIONS

Morphological factors related to hip dysplasia and a shallow acetabulum, which can be assessed with a radiograph alone, were found to be predictors of instability following HA in the elderly. Hemiarthroplasty implant design and manufacturer, and also acetabular version did not contribute to instability risk.

Incidence of dislocation and associated risk factors in patients with a femoral neck fracture operated with an uncemented hemiarthroplasty

BACKGROUND

Several factors might be associated with risk of dislocating following uncemented hemiarthroplasty (HA) due to femoral neck fracture (FNF). Current evidence is limited with great variance in reported incidence of dislocation (1-15%). Aim of this study was to identify the cumulative incidence of first-time dislocation following HA and to identify the associated risk factors.

METHOD

We performed a retrospective cohort study of patients receiving an HA (BFX Biomet stem, posterior approach) at Copenhagen University Hospital, Bispebjerg, in 2010-2016. Patients were followed until death or end of study (dec 2018). Dislocation was identified by code extraction from the Danish National Patient Registry. Variables included in the multivariate model were defined pre-analysis to include: age, sex and variables with a p-value < 0.1 in univariate analysis. A regression model was fitted for 90 days dislocation as the assumption of proportional hazard rate (HR) was not met here after.

RESULTS

We identified 772 stems (some patients occurred with both right and left hip) and 58 stems suffered 90 dislocations during the observation period, resulting in a 7% (CI 5-9) incidence of dislocation 90 days after index surgery. 55 of the 58 stems (95%) experienced the first dislocation within 90 days after surgery. Only absence of dementia was identified as an independent protective factor in the cause-specific model (HR 0.46 (CI 0.23-0.89)) resulting in a 2.4-fold cumulative risk of experiencing a dislocation in case of dementia. Several other variables such as age, sex, various medical conditions, surgery delay and surgical experience were eliminated as statistical risk factors. We found a decrease in survival probability for patients who experienced a dislocation during follow-up.

CONCLUSIONS

The incidence of first-time dislocation of HA (BFX Biomet stem, posterior approach) in patients with a hip fracture is found to be 7% 90 days after surgery. Due to the non-existing attribution bias, we claim it to be the true incidence. Dementia was among several variables identified as the only risk factor for dislocation. In perspective, we may consider treating patients with dementia by other methods than HA e.g., HA with cement or with a more constrained solution. Also, a surgical approach that reduce the risk of dislocation should be considered.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Optimising Soft-Tissue Balancing in Hip Hemiarthroplasty Surgery Using a Simple Planning Protocol

Introduction Intracapsular neck of the femur fractures are some of the most common fragility fractures with significant morbidity and mortality. Cemented hemiarthroplasty is the standard treatment in most cases. Restoring the horizontal offset and leg length is important to optimize the outcome of hip hemiarthroplasty. Preoperative templating based on a scaled radiograph is common prior to total hip arthroplasty surgery to achieve optimum offset and leg length. It is not routine to have scaled radiographs available prior to a hemiarthroplasty surgery. Our simple non-scaled radiograph templating protocol (NSRTP) was introduced to help establish the correct offset and leg length in the absence of scaled radiographs. Methods A retrospective, comparative, case-control study was carried out in an acute hospital setting. Scaled radiographs were not available for any patients in the study, as is usual for hemiarthroplasty patients in our hospital. One group had surgery without any templating. The other group had surgery using the NSRTP. The NSRTP determined optimal ipsilateral offset based on preoperative measurement of the contralateral hip offset and ipsilateral head diameter on unscaled radiographs together with intraoperative measurement of the diameter of the ipsilateral femoral head removed at surgery. To help achieve the correct length, the NSRTP also included assessment and restoration of the contralateral greater trochanter tip-to-head relationship. The neck cut was tailored to restore the correct relationship. Results Twenty-three patients underwent hemiarthroplasty surgery without any templating and 23 had surgery using the NSRTP. The implants used were C-STEM™ (DePuy Synthes, Raynham, Massachusetts, United States) and SPECTRON (Smith & Nephew plc, London, United Kingdom); stems were used together with monopolar heads. The stems were available in standard and high offset versions and with a variety of neck lengths, allowing the correct combination to be selected to restore offset. When the NSRTP was used, horizontal offset and leg length were restored to within 2 mm of the contralateral hip in 22 patients out of 23. There was a statistically significant improvement in restoration of offset and leg length when the NSRTP was used, compared to the control group. Conclusion Restoration of the offset and leg length is important to maximize the outcome of hip arthroplasty surgery. Preoperative templating is helpful to achieve offset and leg length in total hip replacement. In the absence of scaled radiographs, NSRTP enables restoration of offset and leg length to within 2 mm of normal in more than 96% of patients. This protocol requires knowledge of the offset of the hemiarthroplasty stems being used, which is easily available from the relevant manufacturer.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

Dislocation rate, revisions and other complications of primary cemented hemiarthroplasty for displaced femoral neck fractures: a single-center cohort study of 743 unselected hips with a mean 2.7-year follow-up

INTRODUCTION

Evidence of whether to use hemiarthroplasty (HA) or total hip arthroplasty for displaced femoral neck fractures (FNF) is still widely debated, especially when taking ambulatory status, age, and patient cognitive status into account. The current study aims to report the rates of dislocations, revisions and other complications for primary cemented HA in patients with displaced FNF.

MATERIALS AND METHODS

Single-center retrospective follow-up study of an unselected historic cohort. 743 consecutive hips (551 W and 192 M) at mean (SD) age of 83.6 (8.4) years received primary cemented HA for displaced FNF by posterolateral surgical approach between January 2012 and December 2019. Patient files and radiographs were evaluated for dislocations, revisions, and other complications until death or end of the follow-up period, and the educational level of the surgeon was noted.

RESULTS

During a mean (SD) follow-up period of 2.7 (2.2) years, there were 6.1% (n = 45) dislocations, in which 82% (first dislocation) appeared within the first 30 postoperative days, and 51% (n = 23) of the dislocations requiring subsequent surgery. At the time of the last available follow-up, 57% (n = 421) of the patients were dead. A non-dislocation related revision was needed in 3.4% (n = 25) of the patients [in which infection accounted for 40% (n = 10) and traumatic periprosthetic fracture for 32% (n = 8)]. Thirty-day mortality was 9.2% and 1-year mortality 25.8%. There were no differences in patient's age, gender, or educational level of the surgeon between the dislocation and the no dislocation groups. Patients aged < 70 years presented with a higher dislocation rate (p < 0.001) than the patients aged > 70 years.

CONCLUSION

Primary HA presents a safe and robust approach with acceptable complication rates in a genuine unselected cohort of displaced FNF, particularly for patients aged > 70.

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.

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

Introduction

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

Methods

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

Results

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

Conclusion

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

Effect of Vertical and Lateral Offset Restoration on Clinical Outcomes in Intracapsular and Extracapsular Hip Fractures Undergoing Hemiarthroplasty

Objective

We aimed to investigate whether there is a change in the postoperative lateral and vertical femoral offset (FO) in patients who underwent bipolar straight stem hemiarthroplasty (SSHA) and calcar stem hemiarthroplasty (CRHA) and whether this change makes a difference in the comparison of both groups.

Material and methods

This study included 109 patients who met these criteria. Patients are divided into two groups according to treatment methods. There were 58 patients (group 1) who underwent SSHA due to intracapsular (AO type 31-B neck and 31-C head fracture) femur fracture, and there were 51 patients (group 2) who underwent CRHA due to extracapsular (AO type 31-A intertrochanteric) femur fracture. We analyzed femoral vertical and lateral femoral offset, Wiberg angle, and head-neck angle difference in both groups.

Results

The median age was significantly higher in the CRHA group (p=0.042). The Harris hip score (HHS) was significantly higher in the SSHA group (p=0.023). The femoral offset difference was 5 mm in the SSHA group, while it was significantly lower (-6 mm) in the CRHA group (p<0.001). The Wiberg angle difference did not differ significantly between patient groups (p=0.214). The limb length difference was found to be similar in both surgical groups (p=0.483).

Conclusions

The study results show that there was no negative correlation between clinical and radiological outcomes in the SSHA group, whereas there was a negative correlation between clinical and radiological outcomes in the CRHA group. It is very difficult to control vertical and lateral offset reconstruction, especially in extracapsular hip fractures reconstructed by hemiarthroplasty. Deficiencies in lateral and vertical stabilization restoration may be associated with poor clinical outcomes in CRHA patients. Orthopedic surgeries should be performed carefully when restoring leg length and femoral offset, especially calcar replacement hemiarthroplasties.

Established Trauma Triage Score Predicts Risk of Falling After Femoral Neck Fracture Arthroplasty Surgery

INTRODUCTION

The purpose of this study is to determine whether the Score for Trauma Triage in the Geriatric and Middle-Aged (STTGMA) patients is able to predict fall, fracture, periprosthetic fracture, or dislocation risk after femoral neck fracture arthroplasty surgery.

METHODS

Four hundred one patients who underwent hip arthroplasty surgery after a femoral neck fracture at one urban academic medical center were stratified into groups based on their risk scores assigned at femoral neck fracture presentation. The cohort was reviewed for the occurrence of postdischarge falls, secondary fractures, and prosthetic dislocations that resulted in a presentation to the emergency department (ED) after discharge from their hip fracture surgery. The incidence and timing of these complications after discharge were compared between the low-risk and high-risk groups.

RESULTS

The low-risk group included 201 patients, and the high-risk group included 200 patients. The high-risk group had significantly more postdischarge falls resulting in ED presentation (49 vs. 32, p = .035) that occurred significantly sooner (12.6 vs. 18.3 months, p = .034) after discharge.

CONCLUSIONS

The STTGMA model was able to successfully stratify patients who are at a higher risk of sustaining a fall after an arthroplasty procedure for a femoral neck fracture.

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.

Preprosthesis fracture of femoral and loosening of the femoral prosthesis during closed reduction of hip dislocation: A case report

INTRODUCTION

Dislocation after bipolar hip hemiarthroplasty is an uncommon complication. Although closed manoeuvre reduction under general anaesthesia is a common and effective method for dislocation of the hemiarthroplasty. However, closed reduction leads to preprosthesis fracture of femoral and loosening of femoral prosthesis is a rare situation, which requires incision reduction and a revision hemiarthroplasty.

PRESENTATION OF CASE

A 80-year-old female had cementless bipolar hip hemiarthroplasty due to a right femoral neck fracture. At the 11 days of postoperation, the patient had a dislocation of the hemiarthroplasty when squatting. The patient had preprosthesis fracture and loosening of the prosthesis during closed reduction. Eventually, the patient had an open reduction and femoral stem revision. There was no re-dislocation and no re-fracture at one-year follow-up.

DISCUSSION

Closed manoeuvre reduction is a common and effective method for dislocation of the hemiarthroplasty. But if not done properly, it may lead to preprosthesis fracture of femoral and loosening of the femoral prosthesis. Preprosthesis fracture of femoral and loosening of femoral prosthesis is a complex complication. This condition requires operative treatment. A personalized surgical plan and proper techniques should be done before the operation.

CONCLUSION

Closed reduction should be performed gently to avoid preprosthesis fracture and loosening of the prosthesis. If this happens, a high-resolution CT examination should be performed immediately to evaluate the fracture and the rotation of the prosthesis. In the case of dislocation after bipolar hip hemiarthroplasty in patients with Alzheimer's disease, we hypothesize that early wearing braces to limit squat might help prevent this condition.

Risk Factors with Multilevel Evidence for Dislocation in Patients with Femoral Neck Fractures After Hip Hemiarthroplasty: A Systematic Review

BACKGROUND

Hip hemiarthroplasty (HA) is a standard surgical procedure for elderly patients with displaced fracture of the femoral neck, where dislocation is a possible complication. This study is a systematic review on the risk factors of implant dislocation in patients with femoral neck fracture following hip hemiarthroplasty (HA), and evaluates the methodological quality of the included studies.

METHODS

Studies on risk factor assessment of dislocation following hip HA were sourced from EMBASE, Ovid, PubMed and ScienceDirect databases. The quality of included studies was evaluated using an improved quality evaluation method combined with a best-evidence synthesis method.

RESULTS

A total of 130,127 patients were involved in 17 observational studies included in this systematic review, with a dislocation rate that ranged between 0.76 and 12.2% (overall incidence was 4-5% by meta-analysis). According to the applied quality evaluation criteria, eight studies were considered to be of high quality, six to be of medium quality, and three to be of low quality. The posterolateral surgical approach was identified as the only risk factor supported by strong evidence, while patients with small acetabular coverage and low postoperative offset were identified as risk factors supported by moderate evidence, and 11 other risk factors were supported by limited evidence.

CONCLUSION

This systematic review provides some evidence in helping surgeons develop optimal prevention strategies for dislocation following hip HA during the perioperative period based on common risk factors identified in the literature. However, conclusive evidence supporting most of these risk factors is lacking and more methodologically rigorous studies are required to increase the confidence of recommendations.

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.

Morphological risk factors associated with dislocation after bipolar hemiarthroplasty of the hip in patients with femoral neck fractures-a nested case-control study

Background

The relationship between preoperative hip measurements and dislocation after bipolar hemiarthroplasty is presently unclear. In the current study, we investigated the morphological risk factors associated with dislocation after bipolar hemiarthroplasty of the hip in patients with femoral neck fractures.

Methods

Between January 2011 and June 2017, a nested case-control design study was used to analyze the risk factors for dislocation in 348 patients who had undergone bipolar hemiarthroplasty because of femoral neck fractures. Twelve patients underwent at least one dislocation postoperatively. Sixty patients without dislocation were selected as controls matched in terms of time of surgery, age, and sex, at a ratio of 1:5. Patient acetabular measurements were compared between the dislocation group and the control group, including the center-edge angle, abduction angle, acetabular width and depth, depth-to-width ratio, femoral neck offset, leg length discrepancy, and femoral head coverage ratio. A multivariate logistic regression model was used to evaluate the morphological risk factors of dislocation.

Results

Postoperatively, the incidence of dislocation was 3.4%. A smaller center-edge angle was found to be a risk factor associated with dislocation after bipolar hemiarthroplasty of the hip. Patients with small acetabular depth and a small acetabular depth–width ratio were prone to dislocation. Patients with a center-edge angle of ≤ 45.4° or an acetabular depth of ≤ 19.12 mm were more likely to suffer dislocation.

Conclusions

Careful preoperative measurements before bipolar hemiarthroplasty of the hip are important. Surgical intervention for femoral neck fracture patients with a shallow acetabulum should be carefully planned and total hip arthroplasty should be considered when necessary.

Does body mass index affect restoration of femoral offset, leg length and cup positioning after total hip arthroplasty? A prospective cohort study

Background

In obese patients, total hip arthroplasty (THA) can be technically demanding with increased perioperative risks. The aim of this prospective cohort study is to evaluate the effect of body mass index (BMI) on radiological restoration of femoral offset (FO) and leg length as well as acetabular cup positioning.

Methods

In this prospective study, patients with unilateral primary osteoarthritis (OA) treated with THA between September 2010 and December 2013 were considered for inclusion. The perioperative plain radiographs were standardised and used to measure the preoperative degree of hip osteoarthritis, postoperative FO, leg length discrepancy (LLD), acetabular component inclination and anteversion.

Results

We included 213 patients (74.5% of those considered for inclusion) with a mean BMI of 27.7 (SD 4.5) in the final analysis. The postoperative FO was improper in 55% and the LLD in 15%, while the cup inclination and anteversion were improper in 13 and 23% of patients respectively. A multivariable logistic regression model identified BMI as the only factor that affected LLD. Increased BMI increased the risk of LLD (OR 1.14, 95% CI 1.04 to 1.25). No other factors included in the model affected any of the primary or secondary outcomes.

Conclusion

Increased BMI showed a negative effect on restoration of post-THA leg length but not on restoration of FO or positioning of the acetabular cup. Age, gender, OA duration or radiological severity and surgeon’s experience showed no relation to post-THA restoration of FO, leg length or cup positioning.

Effect of articular capsule repair on postoperative dislocation after primary total hip replacement by the anterolateral approach

Objective

Artificial hip dislocation is one of the most serious complications following total hip replacement. This study was performed to assess articular capsule repair in primary total hip replacement with the anterolateral approach (Watson-Jones incision) and its effect on postoperative dislocation.

Methods

Patients who underwent primary total hip replacement by the anterolateral approach in Tongren Hospital of Shanghai Jiao Tong University School of Medicine from June 2007 to June 2014 were retrospectively analyzed. The patients were divided into the repair and dissection groups based on the articular capsule repair status during surgery. Postoperative dislocation rates were compared between the two groups using the chi-squared test.

Results

The repair and dissection groups comprised 137 and 248 patients, respectively. All patients were followed up for 6 months to 5 years (average, 3.75 years). The mean age, sex, disease composition, and follow-up time were not significantly different between the two groups. Early postoperative dislocation occurred in 1 hip (0.7%) in the repair group and 13 hips (5.2%) in the dissection group.

Conclusions

During the anterolateral approach for primary total hip replacement, articular capsule repair may reduce the occurrence of early postoperative dislocation of the hip joint.

Efficacy of Different Posterior Capsulotomies on Dislocations in Hip Hemiarthroplasty: T-Shaped Capsulotomy versus Longitudinal Capsulotomy

BACKGROUND

Dislocation following hip hemiarthroplasty is one of the leading reasons necessitating a resurgery. Many studies suggested that the type of the surgical approach is the main cause for dislocation. However, no consensus has been reached yet regarding the type of the surgical approach. In this prospective clinical study, we aimed to compare the efficacy of two different capsulotomy techniques on dislocations, applied during hip hemiarthroplasties performed through the posterior approach.

MATERIALS AND METHODS

We investigated the dislocation rates in 287 patients (aged 65 and above) who underwent cemented bipolar hemiarthroplasty for displaced femoral neck fractures through the posterior capsular approach using two different capsulotomy techniques between 2009 and 2016. Patients were followed up for 12 months after hemiarthroplasty. Patients were evaluated in two groups; on whom hemiarthroplasty was performed as longitudinal (146 patients) and as T-shaped capsulotomy (141 patients).

RESULTS

Posterior dislocations occurred in seven (5%) patients who underwent hemiarthroplasty with T-shaped capsulotomy. No dislocation was observed in 146 patients who underwent hip hemiarthroplasty through posterior longitudinal capsulotomy. The difference between the two study groups was statistically significant (P < 0.007).

CONCLUSION

Capsule integrity can be achieved through a strong capsule repair which is possible through hemiarthroplasty with longitudinal capsulotomy. Longitudinal capsulotomy is an effective technique in preventing dislocations following hip hemiarthroplasty.

Evaluation and Management of Failed Hemiarthroplasty

Hemiarthroplasty is a common procedure for treatment of displaced femoral neck fractures in low-demand patients. As hip fracture incidence continues to increase, the need for revision hemiarthroplasty is also expected to increase. Multiple etiologies can result in a failed hemiarthroplasty, including persistent pain, infection, instability, leg-length discrepancy, and trauma. Preoperative clinical, radiographic, and laboratory assessments are critical in determining the etiology of the painful hemiarthroplasty. The standard of care for surgical management of failed hemiarthroplasty is conversion to a total hip arthroplasty. However, establishing the etiology preoperatively is essential to planning before treating the failed hemiarthroplasty.

Techniques for the Management of Failed Surgery for Fractures of the Neck of Femur

Background:

The majority of modern surgical treatments for managing hip fracture in the elderly are successful and result in a very low rate of revision surgery. Subsequent operations are however occasionally necessary. Optimal management of complications such as infection, dislocation or failed fixation is critical in ensuring that this frail patient group is able to survive their treatment and return to near normal function.

Methods:

This paper is a discussion of techniques, tips and tricks from a high volume hip fracture unit

Conclusion:

This article is a technique-based guide to approaching the surgical management of failed hip fracture treatment and includes sections on revising both failed fixation and failed arthroplasty.

Reduced revision rate and maintained function after hip arthroplasty for femoral neck fractures after transition from posterolateral to direct lateral approach

Background and purpose - The direct lateral (DL) approach to the hip for femoral neck fractures (FNF) has been shown to reduce the rate of dislocation and reoperations. We evaluate the effect of transition from the posterolateral (PL) to DL approach on reoperation and dislocation rates and patients' reported outcome. Patients and methods - In a prospective cohort study between 2012 and 2015, we enrolled 362 patients (median age 83 years, 70% women, mean follow-up 25 months) with a displaced FNF. The first group of 146 patients were operated using the PL and the second group of 216 patients with a DL approach, after change of our routines. A multivariable Cox regression analysis was used to evaluate factors associated with dislocation and reoperation. A generalized linear model was used to evaluate the functional outcome by comparing WOMAC and Harris hip scores between the 2 groups. Results - The reoperation rate was reduced from 13% in the PL to 6% in the DL group and the dislocation rate from 13% to 4%. Cox proportional hazard analysis identified the PL approach as the only factor associated with an increased risk of reoperation (hazard ratio =2.5, 95% CI 1.2-5.2). Age, sex, ASA classification, type of arthroplasty, cognitive dysfunction, or the experience of the surgeon had no effect on the risk of reoperation. Patient-reported outcome was similar between the 2 groups. Interpretation - In patients with FNF we have reduced the reoperation and dislocation rates by changing the surgical approach used for hip arthroplasty without affecting the patient-reported functional outcome.

Does restoration of leg length and femoral offset play a role in functional outcome one year after hip hemiarthroplasty?

BACKGROUND

The objective of this study was to evaluate the correlation between specific joint biomechanical parameters and 1year functional outcome scores in elderly patients receiving hemiarthroplasty in the setting of intracapsular hip fractures.

METHODS

This is a retrospective, institutional registry based study. 168 hip hemarthroplasties were captured from October 2013 to June 2015. Patients were excluded based on contralateral hip surgery, perioperative complications or inadequate radiographs. 84 patients were alive at one year follow up. We compared mobility and pain scores to radiographically determined variations of leg lengths and femoral offset. We also compared the performance of fellowship trained arthroplasty surgeons to their non-fellowship trained counterparts.

RESULTS

The operated leg was a mean of 1.12±6.8mm longer than the contralateral. leg length discrepancy (LLD) was less than 10mm in 72 patients. Mean difference in offset between limbs was 0.25±3.3mm. The difference was within 5mm in 79 patients (94%). We found no statistically significant correlation between mobility or pain scores and variations in leg length or offset. We found significantly better performance of the arthroplasty surgeons in restoring leg length but no difference in offset reconstruction or functional benefit for the patient.

CONCLUSIONS

Our study was unable to demonstrate a significant relationship between leg length or femoral offset restoration and the patient's ultimate functional recovery. Arthroplasty surgeons performed better in restoring leg length, but no associated functional advantage was seen.

Wiring Techniques for the Fixation of Trochanteric Fragments during Bipolar Hemiarthroplasty for Femoral Intertrochanteric Fracture: Clinical Study and Technical Note

Purpose

Femoral intertrochanteric fractures are common in the elderly. Appropriate surgical fixation of trochanteric fracture fragments can restore normal anatomical structure and ambulation, and can aid in the recovery of biomechanical function of the hip. We evaluated clinical outcomes of bipolar hemiarthroplasty using a wiring technique for trochanteric fracture fragment fixation.

Materials and Methods

From September 2006 to February 2015, a total of 260 cases underwent simultaneous bipolar hemiarthroplasty and wire fixation. A total of 65 patients (69 hips) with an average age of 78 years and more than one year of follow-up was included in the study. Using pre-, postoperative and follow-up radiograms, we evaluated wire fixation failure and also assessed changes in walking ability.

Results

Loosening or osteolysis around the stem was not observed; however, we did observe bone growth around the stem (54 cases), cortical hypertrophy (6 cases), a wide range of sclerotic lines but no stem subsidence (1 case), wire breakage (9 cases), and fracture fragment migration with no significant functional deficiency (2 cases).

Conclusion

Our study showed that additional wiring for trochanteric fracture fragment fixation following bipolar hemiarthroplasty can help restore normal anatomy. The added stability results in faster rehabilitation, and good clinical and radiographic outcomes. We recommend this procedure in this type of fracture.

What Are the Risk Factors for Dislocation of Hip Bipolar Hemiarthroplasty Through the Anterolateral Approach? A Nested Case-control Study

BACKGROUND

Hip dislocation after treatment of a femoral neck fracture with a hemiarthroplasty remains an important problem in the treatment of hip fractures, but the associations between patient factors and surgical factors, and how these factors contribute to dislocation in patients who have undergone bipolar hemiarthroplasty through an anterolateral approach for femoral neck fracture currently are only poorly characterized.

QUESTIONS/PURPOSES

We evaluated patients with bipolar hemiarthroplasty dislocation after surgery for femoral neck fracture treated through an anterolateral approach and asked: (1) What are the frequency, characteristics, and risk factors of bipolar hemiarthroplasty dislocations? (2) What are the frequency, characteristics, and risk factors of bipolar hemiarthroplasty dissociations?

METHODS

A review of hospital records for patients who underwent bipolar hip hemiarthroplasty for femoral neck fracture at one hospital between July 2004 and August 2014 was conducted. During that time, 1428 patients were admitted with a diagnosis of femoral neck fracture; 508 of these patients underwent bipolar hip hemiarthroplasty, of whom 61 died and 23 were lost to followup during the first year, leaving 424 (83%) available for analysis. The remainder of the patients during that time were treated with internal fixation (512), unipoloar hip arthroplasty (17), or THA (391). For each patient with dislocation, we selected five control patients from the cohort according to sex, age (± 3 years), and year of entry in the study to eliminate some confounding factors. We recorded patient characteristics regarding demographics, medical comorbidities, Katz score, American Society of Anesthesiologists score, Mini-Mental State Examination (MMSE) score, and anesthesia type. Medical comorbidities included diabetes, chronic pulmonary disease, heart disease, neuromuscular diseases, and dementia. Univariate analyses were used to search for possible risk factors. Conditional logistic regression analyses on dislocation or dissociation were performed to estimate hazard rates (HRs) and corresponding 95% CIs with covariates of a probability less than 0.1 in univariate analysis.

RESULTS

In this cohort, there were 26 dislocations including four that were also dissociations. The proportion of patients experiencing a dislocation was 6% (26 of 424). The mean interval from surgery to dislocation was 56 weeks (range, 0-433 weeks), and 18 dislocations (69%) occurred within 3 months after surgery. Three variables were independently associated with an increased risk of hip dislocation: dementia (HR, 3.51; 95% CI, 1.19-10.38; p = 0.02), discrepancy of offset (HR, 1.72; 95% CI, 1.15-2.58; p = 0.008), and lower MMSE score (HR, 0.93; 95% CI, 0.88-0.98; p = 0.007). The proportion of patients experiencing a dissociation was 0.9% (four of 424). The result of conditional logistic regression for dissociation showed that cup size smaller than 43 mm was the risk factor (HR = 513.05). However, there was no statistical difference with the probability equaling 0.47.

CONCLUSIONS

After the anterolateral approach for treatment of femoral neck fracture using bipolar hemiarthroplasty, 6% of hips dislocated and 0.9% experienced dissociation. Cognitive dysfunction and discrepancy of offset were independent risk factors associated with an increased risk of prosthetic dislocation. The small cup without a safety ring may be the risk factor of dissociation. Discrepancy of offset should be avoided during the operation by performing an accurate femoral osteotomy and choosing an adequate femoral stem neck length. For patients with cognitive dysfunction and a small cup, suturing the joint capsule during the operation and reinforcing protective measures after surgery might reduce the occurrence of dislocation and dissociation, however a study addressing this is necessary to confirm this.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Risk Factors Associated with Dislocation after Bipolar Hemiarthroplasty in Elderly Patients with Femoral Neck Fracture

Purpose

We investigated the incidence and time of dislocation and other factors associated with dislocation of bipolar hemiarthroplasty related to the treatment of femoral neck fracture in old age patients.

Materials and Methods

Between January 2002 and April 2014, 498 femoral neck fractures (467 patients) were treated with bipolar hemiarthroplasty and included in this study. All surgeries were performed using the postero-lateral approach. The incidence of dislocation was investigated. A comparative analysis between a control group and dislocation group was performed with respect to patient factors including age, gender, body mass index, comorbidities, the ASA (American Society of Anesthesiologists) score, mental status and center-edge angle, and surgical factors including type of femoral stem, leg length discrepancy, femoral offset and method of short external rotator (SER) reconstruction.

Results

The incidence of dislocation was 3.8%, and the dislocation occurred on average 2.2 months (range, 0.6-6.5 months) after operation. No difference in patient-related factors was observed between the two groups. However, a smaller center edge (CE) angle was observed in the dislocation group (42.1°±3.2° vs. 46.9°±5.4°, P<0.001), and significantly lower incidence of dislocation was observed in tendon to bone repair group (0.7% vs 7.8%, P<0.001).

Conclusion

SERs should be repaired using the tendon-to-bone repair method to reduce dislocation rate in elderly patients who undergo bipolar hemiarthroplasty using the postero-lateral approach due to femoral neck fracture. In addition, patients with smaller CE angle should be carefully monitored due to high incidence of dislocation.