Functional implications of femoral offset following hemiarthroplasty for displaced femoral neck fracture

Analysis of risk factors for modification of femoral offset after internal fixation of Garden I and II femoral neck fractures

BACKGROUND

The concept of restoring the femoral offset is well established during hip replacement surgery, but is less well known when treating Garden I or II femoral neck fractures by internal fixation. And yet, the therapeutic aim for these fractures is to restore this native parameter as best possible. The aim of this study was to identify the risk factors for reduction of femoral offset after union of a Garden I or II femoral neck fracture treated by internal fixation.

HYPOTHESIS

After internal fixation of a femoral neck fracture, certain factors may contribute to reducing the femoral offset, which itself has been identified as being responsible for altering the patients' quality of life and functional outcomes.

MATERIALS AND METHODS

This multicenter study included 193 patients who had a Garden I or II femoral neck fracture treated by cannulated screws or a sliding compression screw-plate. The difference between the femoral offset in the operated hip and that of the contralateral hip was measured in weightbearing patients after the fracture had healed. This difference was the primary outcome measure. Univariate and multivariate analyses were done to look for risk factors contributing to femoral neck shortening.

RESULTS

Based on the univariate analysis, being more than 85 years of age, having a Garden I fracture, and cannulated screw fixation were associated with a significantly greater reduction in the femoral offset. In the multivariate analysis, only Garden I fractures were associated with a greater reduction in femoral offset.

DISCUSSION

Garden I fractures were associated with a greater reduction in the offset, although there was no evidence that this change was related to early weightbearing. By identifying this risk factor, surgeons can optimize the indications given that the treatment of these fractures is still widely debated and there is still no consensus as to the best method.

LEVEL OF EVIDENCE

IV.

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.

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.].

Anatomical and Simulation Studies Based on Three-Dimensional-Computed Tomography Image Reconstruction of Femoral Offset

Although the hip joint morphology varies by race, few studies have investigated the associations between two-dimensional (2D) and three-dimensional (3D) morphologies. This study aimed to use computed tomography simulation data and radiographic (2D) data to clarify the 3D length of offset, 3D changes in the hip center of rotation, and femoral offset as well as investigate the anatomical parameters associated with the 3D length and changes. Sixty-six Japanese patients with a normal femoral head shape on the contralateral side were selected. In addition to radiographic femoral, acetabular, and global offsets, 3D femoral and cup offsets were investigated using commercial software. Our findings revealed that the mean 3D femoral and cup offsets were 40.0 mm and 45.5 mm, respectively; both were distributed around the mean values. The difference between the 3D femoral and cup offsets (i.e., 5 mm) was associated with the 2D acetabular offset. The 3D femoral offset was associated with the body length. In conclusion, these findings can be applied to the design of better ethnic-specific stem designs and can help physicians achieve more accurate preoperative diagnoses.

Short- and long-term prognostic factors associated with functional recovery in elderly patients with hip fracture: A systematic review

This systematic review aimed to identify short- and long-term associated factors to functional recovery of elderly hip fracture patients after discharge. We identified 43 studies reporting 74 associated factors to functional recovery; most of them were biological, sociodemographic, or inherent factors to patients' baseline characteristics, including their pre-facture functional capacity.

PURPOSE

This systematic review aimed to identify short- and long-term associated factors to functional recovery of elderly hip fracture patients after hospital discharge. We assessed the use of the hip fracture core-set and key-performance indicators for secondary fracture reduction.

METHODS

A search was performed in seven electronic databases. Observational studies reporting predictors after usual care of elderly patients with hip fracture diagnoses receiving surgical or conservative treatment were included. Primary outcomes considered were part of the domains corresponding to functional capacity.

RESULTS

Of 3873 references identified, and after the screening and selection process, 43 studies were included. Sixty-one functional measures were identified for ten functional outcomes, including BADLs, IADLs, ambulation, and mobility. Biological characteristics such as age, sex, comorbidities, cognitive status, nutritional state, and biochemical parameters are significantly associated. Determinants such as contact and size of social network and those related to institutional care quality are relevant for functional recovery at six and 12 months. Age, pre-fracture function, cognitive status, and complications continue to be associated five years after discharge. We found 74 associated factors to functional recovery of elderly hip fracture patients. Ten of the studies reported rehabilitation programs as suggested in KPI 9; none used the complete hip fracture core-set.

CONCLUSION

Most of the associated factors for functional recovery of elderly hip fracture were biological, sociodemographic, or inherent factors to patients' baseline characteristics, including their pre-facture functional capacity. For the core-set and KPI's, we found an insufficient use and report. This study reports 61 different instruments to measure functional capacity.

REGISTRATION NUMBER

PROSPERO (CRD42020149563).

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.

INFLUENCE OF FEMORAL OFFSET ON FUNCTIONAL CAPACITY OF PATIENTS WITH TOTAL HIP ARTHROPLASTY

Objective

To correlate vertical (VFO) and horizontal (HFO) femoral offset with hip range of motion (ROM), peak muscle torque (PT), functional, capacity, and lower limb length in patients with total hip arthroplasty (THA).

Methods

A cross-sectional case control study, in which 22 individuals (10 men and 12 women) - aged 61 (41-72), and within 23 (10-40) postoperative days - were evaluated for active hip ROM (fleximetry); Isometric PT (portable dynamometer); functional capacity (Timed up and Go test (TUG) and Harris Hip Score questionnaire); lower limb length (measuring tape); and VFO and HFO (radiographs).

Results

The operated limb showed a reduction in length (p = 0.006), ROM for abduction (p = 0.001), flexion (p = 0.003), and external rotation (p = 0.003), as well as in all PT (p < 0.05) when compared with the contralateral limb. Moderate correlations were observed between VFO and external rotators (r = 0.487; p = 0.021); HFO and external rotators PT (r = -0.508; p = 0.016); and the difference between the VFO (operated and non-operated limb) and the TUG (r = -0.570; p = 0.006).

Conclusion

Changes to the femoral offset seem to influence functional capacity, as well as the movement and external rotators PT of the hips in patients with THA, considering the postoperative period evaluated. Level of Evidence III, Case Control Study.

Comparing Postoperative Leg Length Discrepancy and Femoral Offset Using Two Different Surgical Approaches for Hemiarthroplasty of the Hip

INTRODUCTION

The direct anterior approach (DAA) and anterolateral approach (ALA) may be used for hip hemiarthroplasty (HHA) as a treatment for femoral neck fractures. The DAA often utilizes intraoperative fluoroscopy to determine leg length and offset, while the ALA traditionally utilizes an intraoperative clinical exam to determine offset and leg length. This study will evaluate two techniques: the "grid fluoroscopy [GF] technique" and the "intraoperative exam [IE] technique," each performed by one of two separate surgeons, and compare each technique's accuracy to restore leg length and femoral offset in a patient population that underwent HHA.

METHODS

Two investigators retrospectively reviewed charts of 208 randomly selected patients who had an HHA from either a DAA or ALA performed by two different surgeons for the treatment of femoral neck fractures. Postoperative AP pelvis radiographs were measured to determine offset and leg length compared with the non-operative extremity. Non-normal continuous variables were provided by median and interquartile range. Data were analyzed with the Mann-Whitney U test and Student's t-test.

RESULTS

After inclusion and exclusion criteria, data were reviewed on 173 hemiarthroplasties. The mean age was 80.3 years (± 11.2 years). Of the surgical patients, 65.9% were female, and 70.9% identified their ethnicity as white. The DAA was used in 93 patients and ALA in 80 patients. Analysis comparing the two techniques demonstrated no statistically significant differences in median leg length between GF technique (1.02 IQR -0.1, 2.0 mm) and IE technique (1.25 IQR -2.4, 1.3 mm,) (p=0.67). There was also no statistically significant difference in offset between GF technique (1.3 IQR 0.2, 2.1 mm) and IE technique (0.6 IQR -2.7 mm, 3.2 mm) (p=0.13). However, a difference was found in mean length of surgery that was statistically significant. We found that the mean length of surgery for the IE technique was 74.8 ± 24.7 minutes versus the GF technique, which was 95.1 ± 23.0 minutes, (p<0.0001).

DISCUSSION

There was no significant difference between leg length and offset with the use of intraoperative fluoroscopy with DAA compared to no intraoperative imaging with ALA. Our study suggests that DAA and ALA are equally effective approaches for re-establishing symmetric leg length and offset in HHA for femoral neck fractures. In this study, the ALA had a shorter surgical time compared to DAA, potentially due to the utilization of intraoperative fluoroscopy for this particular technique during the DAA.

Mismatch between Conventional Femoral Arthroplasty Stems and Hip Morphology in the Elderly Chinese Hip Fracture Population

INTRODUCTION

The morphology of the proximal femur differs in various populations. Based on our clinical experience, conventional femoral stems used in hip arthroplasty do not fit the Chinese population well. Hence, this study aims to evaluate the suitability of conventional femoral stems in the elderly Chinese hip fracture population requiring hip arthroplasty and to establish if gender and age related differences exist within this population.

MATERIAL AND METHODS

We retrospectively analysed radiographic data of 300 patients from a tertiary hospital's geriatric hip fracture database who underwent either hip hemi-arthroplasties or total hip arthroplasties. Proximal femur morphological measurements were recorded, analysed and compared to that of commonly used femoral stems. Subgroup analysis was performed to compare age and gender related differences.

RESULTS

A total of 18.3% of the study population had a medial femoral offset (MFO) of less than 30mm, which is the smallest available offset for the implants studied. 22.6% of female and 3% of male subjects had MFOs that were less than 30mm. In our subgroup analysis, males had significantly larger femoral head diameters, MFO and vertical femoral offsets compared to females. Older subjects (75-90 years old) had significantly smaller femoral head diameters, vertical femoral offsets and neck shaft angles compared to younger subjects (60-75 years old).

CONCLUSION

Commonly used femoral stem implants have measurements that do not suit our Chinese population with small medial femoral offsets. In addition, elderly males have significantly larger femoral head diameters, medial and vertical femoral offsets whereas older subjects have significantly smaller femoral head diameters, vertical femoral offsets and neck shaft angles.

Relationships between Femoral Offset Change and Clinical Score following Bipolar Hip Arthroplasty in Femoral Neck Fractures

Purpose

This study aimed to investigate the relationship between femoral offset (FO) and clinical outcomes of patients with femoral neck fracture following bipolar hip arthroplasty (BHA).

Materials and Methods

Records for a total of 520 patients who underwent BHA for a femoral neck fracture between December 1, 2003, and September 30, 2018, were reviewed retrospectively. Patients with unclear medical records, a congenital deformity and preoperative trauma history of the hip, high-energy multiple trauma, or a history of neurodegenerative disease or cerebrovascular disease were excluded. The remaining 77 patients included in the analysis had a minimum follow-up period of one year. For clinical assessment, the postoperative pain visual analogue scale (VAS) and Harris hip score (HHS) were analyzed at each follow-up period. For radiological assessment, the difference in leg length discrepancy (LLD) and FO were measured.

Results

The difference in mean FO postoperatively was 6.7±4.8 mm, and the difference in mean postoperative LLD was 4.9±3.4 mm. The mean HHS was 77.1±7.7, 82.3±8.6, 83.4±7.7, and 86.4±6.7 at 1, 3, 6, and 12 months postoperative, respectively. The correlation coefficient between FO and HHS in 1-year follow-up was −0.38, and a statistically significant outcome was found (P=0.001). For the HHS domain, the correlation coefficient for function at 1-year follow-up was −0.42, revealing a statistically significant outcome (P=0.0001).

Conclusion

There was a statistically significant correlation between clinical outcomes and FO difference at 1 year after BHA in patients over 65 years of age with femoral neck fractures.

The effect of postoperative femoral offset on outcomes after hip arthroplasty: A systematic review

The purpose of this systematic review was to analyze the effect of decreased, restored, or increased femoral offset on patient reported outcomes (PROs) following hip arthroplasty. Databases were searched according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. With regard to Harris Hip Score, two studies reported superior outcomes for the increased femoral offset group, one study reported superior outcomes for a restored offset group, and the final study reported favorable outcomes for the decreased offset group. Patients with restored offset following arthroplasty may demonstrate superior PROs.

Value of 3D Preoperative Planning for Primary Total Hip Arthroplasty Based on Biplanar Weightbearing Radiographs

Two-dimensional (2D) planning on standard radiographs for total hip arthroplasty may not be sufficiently accurate to predict implant sizing or restore leg length and femoral offset, whereas 3D planning avoids magnification and projection errors. Furthermore, weightbearing measures are not available with computed tomography (CT) and leg length and offset are rarely checked postoperatively using any imaging modality. Navigation can usually achieve a surgical plan precisely, but the choice of that plan remains key, which is best guided by preoperative planning. The study objectives were therefore to (1) evaluate the accuracy of stem/cup size prediction using dedicated 3D planning software based on biplanar radiographic imaging under weightbearing and (2) compare the preplanned leg length and femoral offset with the postoperative result. This single-centre, single-surgeon prospective study consisted of a cohort of 33 patients operated on over 24 months. The routine clinical workflow consisted of preoperative biplanar weightbearing imaging, 3D surgical planning, navigated surgery to execute the plan, and postoperative biplanar imaging to verify the radiological outcomes in 3D weightbearing. 3D planning was performed with the dedicated hipEOS® planning software to determine stem and cup size and position, plus 3D anatomical and functional parameters, in particular variations in leg length and femoral offset. Component size planning accuracy was 94% (31/33) within one size for the femoral stem and 100% (33/33) within one size for the acetabular cup. There were no significant differences between planned versus implanted femoral stem size or planned versus measured changes in leg length or offset. Cup size did differ significantly, tending towards implanting one size larger when there was a difference. Biplanar radiographs plus hipEOS planning software showed good reliability for predicting implant size, leg length, and femoral offset and postoperatively provided a check on the navigated surgery. Compared to previous studies, the predictive results were better than 2D planning on conventional radiography and equal to 3D planning on CT images, with lower radiation dose, and in the weightbearing position.

Modular Versus Monoblock Hemiarthroplasty in Trauma: A 5-Year Retrospective Analysis of Radiographic and Clinical Outcomes

Introduction:

Displaced intraarticular neck of femur fractures for low-demand patients are primarily managed with hemiarthroplasty. The optimal implant design for modularity is unclear. Globally and within Australia, the use of monoblock implants varies significantly by location; however, monoblock use is decreasing in Australia in favour of modular systems, with little evidence-based explanation. This study aimed to compare the radiological and clinical outcomes of monoblock and modular hemiarthroplasties.

Methods:

This retrospective cohort study involved patients who underwent hemiarthroplasty for neck-of-femur fractures between 2009 and 2013 at the Gold Coast University Hospital. Leg length and femoral offset were measured from post-operative pelvic radiographs. Revision and mortality rates were extracted from hospital medical records and Australian Joint Registry data.

Results:

A total of 249 patients were evaluated (112 with modular and 147 with monoblock implants). Patient demographics were comparable between the treatment groups; however, the monoblock group comprised significantly older persons. No between-group differences in leg length discrepancies were identified. Femoral offset was under-restored on average by 5.86mm (p<0.05) compared to the uninjured side within the monoblock group. Mortality rates were significantly higher in the monoblock group (23% vs 12%, P=0.026) at the 1-year mark. No significant between-group differences were found in 30-day mortality, length of stay, or revision rates.

Discussion:

Modular hemiarthroplasty was superior for restoring offset in our cohort, but no group differences were noted for leg length. While modular implants seemed better for restoring normal hip anatomy and were associated with a lower 1-year mortality rate, no other advantages were found.

Risk factors for prolonged operative time in femoral neck fracture patients undergoing hemiarthroplasty through direct anterior approach

BACKGROUND

The use of direct anterior approach (DAA) for hemiarthroplasty in femoral neck fracture patients has recently increased worldwide. However, no previous studies have elucidated or validated risk factors for prolonged operative time in hemiarthroplasty through DAA. Accurately predicting operative time would contribute to and the selection of the most appropriate surgical approach for each patient and the effective use of operating room.

METHODS

Data from 151 femoral neck fracture patients who underwent hemiarthroplasty through DAA were evaluated. A multiple linear regression model of the operative time of hemiarthroplasty was developed, including age, sex, body mass index (BMI), surgeons' DAA experience and approach depth (cm) on the axial computed tomography (CT) slice of the hip as independent factors.

RESULTS

Mean age at admission was 83.8 [±6.3 standard deviation (SD)] years and mean operative time was 93.1 (±21 SD) min. Operative time increased by 20 min for every 1 cm increase in approach depth [partial regression coefficient (B), 20.4; standardized partial regression coefficient (β), 0.68; p < 0.001] and increased 13 min when the DAA was performed by a surgeon with DAA experience of <20 cases (B, 13.1; β, 0.29; p < 0.001). The adjusted R² of the model was 0.57.

CONCLUSIONS

We demonstrated that increased approach depth and surgeons' DAA experience (<20 cases) are novel risk factors for prolonged operative time in femoral neck fracture patients undergoing hemiarthroplasty through DAA. Surgeons should consider these factors when estimating the operative time of surgery and selecting the most appropriate and safe surgical approach for a patient undergoing hemiarthroplasty.

Hip Hemiarthroplasty in Neurologic or Cognitively Impaired Patients: A Case Series of Post-operative Dislocations

Introduction:

Hemiarthroplasty is the operation of choice for displaced intracapsular neck of femur fracture in elderly patients with low physical demands. Dislocation in this frail patient cohort can have devastating consequences. The patients with neurological and cognitive impairment are at additional risk secondary to imbalance of muscle tone and a reduced ability to engage with rehabilitation.

Case Report:

We present three cases of early post-operative dislocation of hip hemiarthroplasties, all of whom suffered from neurological and cognitive impairment, and highlight the uncontrollable patient factors that contributed to dislocation.

Conclusion:

The posterior approach was associated with all cases of dislocation in patients who also were neurologic or cognitively impaired. Posterior approach is safe to perform in the general population for hip hemiarthroplasty; however, the surgeon should consider avoiding the use of the posterior approach in this high-risk group.

Prospective comparison of the anterior and lateral approach in hemiarthroplasty for hip fractures: a study protocol

Background

The Direct Anterior Approach (DAA) is an alternative approach to the currently most used Lateral Approach (LA) for hip replacement in femoral neck fracture patients. Compared to the LA, the DAA minimizes soft tissue damage. Sparing muscle tissue may facilitate early and improved postoperative mobility. It may also be associated with fewer complications, increased quality of life and lower 1-year mortality. The aim of this study is to compare postoperative complications, hip function and patient mobility after hemiarthroplasty via the anterior or lateral approach following a displaced femoral neck fracture.

Methods

138 elderly patients with displaced femoral neck fractures will be operated using either the direct anterior approach or the lateral approach for a hemiarthroplasty in a single centre, prospective, comparative cohort study. The choice of surgical approach will depend on the expertise of the trauma surgeon on call. The primary outcome of this study will be the functionality of the hip after surgery measured using the Harris Hip Score during routine outpatient check-ups. Secondary outcomes include surgical and non-surgical complication rates, admission time, postoperative pain, rehabilitation time, performance in activities of daily living, health-related quality of life measured, cognitive function and balance.

Discussion

Many approaches are known for hip replacement arthroplasty in trauma patients with little consensus on the preferred method. Identifying the best approach facilitating an adequate and fast recovery could optimize patient independence and quality of life and minimize rehabilitation costs, morbidity and mortality rates. The study design will reflect daily clinical practice and aims to present an accurate depiction of clinical outcomes.

Trial registration

This trial entered the Dutch Trial Registry with registration number (NTR)6238 on the 24th of April 2017. http://www.trialregister.nl/trialreg/index.asp. Protocol version 2.0 16–03-2017.

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.

Does femoral offset recover and affect the functional outcome of patients with displaced femoral neck fracture following hemiarthroplasty?

BACKGROUND

Restoring preoperative horizontal femoral offset (FO) promised good functional outcome in patients receiving total hip arthroplasty. However, relatively little was known regarding the clinical relevance of restoring the offset in patients with bipolar hemiarthroplasty to treat displaced femoral neck fracture. Therefore, the objective of this study was to evaluate postoperative FO accurately and verify its relation with functional outcome.

METHODS

One hundred elderly patients who received bipolar hemiarthroplasty to treat displaced femoral neck fracture were identified. Preoperative CT scanning of contralateral hip joint and reconstruction of images led to rotation-free FO. By referencing postoperative implant specification and comparing to measured values in Picture Archive and Communication System, rotation-free postoperative FO and the amount of change were acquired. Postoperative Harris Hip Score (HHS) and Modified Barthel Index (MBI) were evaluated to measure functional outcome at 12-month after the surgery. Patients with significant FO change were identified. Multiple regression analysis was conducted to determine if the FO change might independently affect the outcome regardless of confounding factors.

RESULTS

The mean preoperative offset was 37.4±2.5 increased by 12.7±9.6% after the surgery. Only 25.0% of postoperative offset after hemiarthroplasty was changed within ±5% of preoperative offset. A total of 45.0% of postoperative offset changed within ±10% while 77.0% of postoperative offset changed within ±20%. 23% of patients whose FO changed more than 20% showed significantly worse outcome score than the patients whose FO change remained within ±20% of initial value. Mean MBI and HHS were negatively correlated with FO change. After adjusting for confounding factors, significant correlation remained between modification of FO and MBI, but not between FO change and HHS (B=4.576; β=0.235; 95% confidence interval of B: 0.534 to 8.135).

CONCLUSIONS

FO was not properly restored in 23% of subjects receiving bipolar hemiarthroplasty due to femoral neck fracture. FO restoration independently predicted fair MBI after the surgery. Therefore, surgeons should pay attention to restoring FO with meticulous templating.

The value of modular hemiarthroplasty for unstable femoral neck fractures in elderly patients with coxarthrosis

Background

Displaced femoral neck fractures are common in the elderly patient. The surgical treatment options consist of a hemiarthroplasty (HA) or total hip arthroplasty (THA). However, the best surgical choice is still under debate. Bipolar HAs do not address preexisting arthritic changes of the acetabulum, which may lead to an unfavorable clinical outcome. The purpose of the present study was to conduct a long term follow-up analysis of the bipolar hemiarthroplasty with particular focus on the influence of preoperative acetabular osteoarthritis on the functional outcome.

Methods

In a retrospective observational study, the medical charts of consecutive patients treated with a bipolar hemiarthroplasty at a level one trauma center between 2004 and 2008 were reviewed before a final radiographic and clinical follow-up was performed. The outcome variables consisted of arthritic findings on the pre- and postoperative x-rays with particular focus on double fond osteophyte (DFO) and posterior wall sign (PWS) as well as the revision rate and functional scores.

Results

This study included 102 patients with a mean age of 77.2 years. Most patients (75 %) had a Kellgren-Lawrence grading scale (KLGS) of 2 or 3. While only 30 % of patients had a DFO, most patients (73 %) had a PWS. The DFO correlated significantly with the KLGS, but no correlation was seen with the clinical outcome. Most patients showed a decreased offset by a mean of −7.8 mm. The mean modified Harris Hip Score (HHS) of 90.3 and the mean Merle d'Aubigné score of 10.8 correlated significantly. Despite a significant correlation of the HSS subcategory of pain and the preoperative KLGS, there was no statistical relationship between the arthritic x-ray measurements and the clinical outcome.

Conclusions

In the presented study population, the presence of radiographic acetabular osteoarthritis did not influence the clinical outcome after bipolar hemiarthroplasty for displaced femoral neck fractures.

The neck shaft angle: CT reference values of 800 adult hips

OBJECTIVE

A precise understanding of the radiological anatomy and biomechanics as well as reliable reference values of the hip are essential. The primary goal of this study was to provide reference values of the neck-shaft angle (NSA) for adult patients based on the analysis of rotation corrected computed tomography (CT) scans of 800 hips. The secondary aim was to compare these measurements with simulated anteroposterior roentgenograms of the pelvis.

MATERIALS AND METHODS

Pelvic CT scans of 400 patients (54.3 years, range 18-100 years; 200 female) were reconstructed in the derotated coronal plane of the proximal femur and as CT-based simulated anteroposterior roentgenograms of the pelvis in the anterior pelvic plane. Femora were categorized as coxa vara (<120°), physiologic (≥120° to <135°), and coxa valga (≥135°). Intra- and inter-rater reliability were analyzed.

RESULTS

Primary research question: Mean NSA for male adults was 129.6° (range 113.2°-148.2°; SD 5.9°) and 131.9° (range 107.1°-151.9°; SD 6.8°) for females in derotated coronal reconstructions. Age (p < 0.001 in both views) and sex influenced the NSA significantly (p = 0.002 and p < 0.001); no significant differences were found between sides (p = 0.722 and p = 0.955). Overall, an excellent reliability of repeated measurements of one or two observers was found (ICC 0.891-0.995). Secondary research question: NSA values measured in the simulated anteroposterior roentgenogram and the rotation corrected coronal reconstruction differed significantly (p < 0.001).

CONCLUSIONS

While anteroposterior pelvis radiographs are susceptible to rotational errors, the coronal reconstruction of the proximal femur in the femoral neck plane allows the correct measurement of the NSA.

The femoral neck-shaft angle on plain radiographs: a systematic review

OBJECTIVE

The femoral neck-shaft angle (NSA) is an important measure for the assessment of the anatomy of the hip and planning of operations. Despite its common use, there remains disagreement concerning the method of measurement and the correction of hip rotation and femoral version of the projected NSA on conventional radiographs. We addressed the following questions: (1) What are the reported values for NSA in normal adult subjects and in osteoarthritis? (2) Is there a difference between non-corrected and rotation-corrected measurements? (3) Which methods are used for measuring the NSA on plain radiographs? (4) What could be learned from an analysis of the intra- and interobserver reliability?

MATERIAL AND METHODS

A systematic literature search was performed including 26 publications reporting the measurement of the NSA on conventional radiographs.

RESULTS

The mean NSA of healthy adults (5,089 hips) was 128.8° (98-180°) and 131.5° (115-155°) in patients with osteoarthritis (1230 hips). The mean NSA was 128.5° (127-130.5°) for the rotation-corrected and 129.5° (119.6-151°) for the non-corrected measurements.

CONCLUSION

Our data showed a high variance of the reported neck-shaft angles. Notably, we identified the inconsistency of the published methods of measurement as a central issue. The reported effect of rotation-correction cannot be reliably verified.