Valgus-impacted Femoral Neck Fractures Research Articles

Screw Configuration Does Not Significantly Alter Neck Shortening After Valgus-Impacted Femoral Neck Fracture (OTA Type 31B1.1).

To compare 3 different cancellous screw configurations used for Garden 1 femoral neck fractures (FNFs). Retrospective review. A large urban academic medical center. All patients with OrthopaedicTrauma Association 31B1.1 FNF who underwent in situ fixation with cancellous screws between 2012 and 2021 were included. Patients were divided into 3 groups: 2 screws placed in a parallel fashion, 3 screws placed in an inverted triangle configuration, and 3-screw fixation with placement of 1 "out-of-plane" screw perpendicular to the long axis of the femur. Postoperative femoral neck shortening (mm) was the primary outcome, which was compared among the 3 groups of different screw configurations. Sixty-one patients with a median follow-up of 1 year (interquartile range 0.6-1.8 years) and an average age of 72 years (interquartile range 65.0-83.0 years) were included. All fractures demonstrated bony healing. Overall, 68.9% of the cohort had ≤2 mm of femoral neck shortening. There was no difference between groups in the proportion of patients who experienced greater than 2 mm of shortening (P = 0.839) or in the amount (mm) of femoral neck shortening (Kruskal-Wallis χ2 = 0.517, P = 0.772). Although most patients with valgus-impacted FNF treated with screw fixation do not experience further femoral neck shortening, some patients demonstrated continued radiographic shortening during the healing process. The development of further femoral neck shortening and the amount of shortening that occurs do not differ based on implant configuration. Multiple different screw configurations seem to be acceptable for achieving healing and minimizing further femoral neck impaction. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

High Complication Rate After Percutaneous Screw Fixation for Valgus-Impacted Femoral Neck Fractures Without Sagittal Malalignment.

To evaluate the rate of reoperation in patients without sagittal plane malalignment who underwent percutaneous screw fixation of a valgus-impacted femoral neck fracture. Retrospective case series. Two Level 1 academic trauma centers. Two hundred seven patients >50 years of age with valgus-impacted femoral neck fractures treated with at least 3 large-diameter (>6.5 mm) cancellous screws from 2013 to 2019. Patients were excluded if there was a sagittal plane fracture deformity. The primary outcome was reoperation. Secondary outcomes considered "major complications" included: avascular necrosis, varus collapse or implant cutout, nonunion, deep infection, and hematoma requiring reoperation. Surgical fixation strategies (screw configuration, aim) and implant type (partial vs. fully threaded cancellous screws) were secondarily compared. Average patient age was 77 years, and median clinical follow-up was 658 days. Thirty-one patients (15%) required reoperation, and the major complication rate was 17.3% (36 complications in 33 patients). Logistic regression analysis demonstrated a higher risk of reoperation with constructs consisting of all partially threaded screws (17.0%) compared with the use of at least 1 fully threaded screw (7.5%) when an inverted triangle configuration was used (odds ratio, 2.50; 95% CI, 0.81-7.77). This study demonstrated a relatively high rate of reoperation and major complications in patients with valgus-impacted femoral neck fractures without sagittal malalignment treated with in situ percutaneous screw fixation. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Can a Computer-based Force Feedback Hip Fracture Skills Simulator Improve Clinical Task Performance? A Cadaveric Validation Study.

This cadaveric study seeks to determine whether skills acquired on the simulator translate to improved performance of the clinical task. We hypothesized that completion of simulator training modules would improve performance of percutaneous hip pinning. Eighteen right-handed medical students from two academic institutions were randomized: trained (n = 9) and untrained (n = 9). The trained group completed nine simulator-based modules of increasing difficulty, designed to teach techniques of placing wires in an inverted triangle construct in a valgus-impacted femoral neck fracture. The untrained group had a brief simulator introduction but did not complete the modules. Both groups received a hip fracture lecture, an explanation and pictorial reference of an inverted triangle construct, and instruction on using the wire driver. Participants then placed three 3.2 mm guidewires in cadaveric hips in an inverted triangle construct under fluoroscopy. Wire placement was evaluated with CT at 0.5 mm sections. The trained group significantly outperformed the untrained group in most parameters (P ≤ 0.05). The results suggest that a force feedback simulation platform with simulated fluoroscopic imaging using an established, increasingly difficult series of motor skills training modules has potential to improve clinical performance and might offer an important adjunct to traditional orthopaedic training.

Application of percutaneous screwdriver rod-assisted closed reduction in treatment of valgus-impacted femoral neck fractures

To evaluate the feasibility and effectiveness of percutaneous screwdriver rod-assisted closed reduction in the treatment of valgus-impacted femoral neck fractures. Between January 2021 and May 2022, 12 patients with the valgus-impacted femoral neck fractures were treated with percutaneous screwdriver rod-assisted closed reduction and femoral neck system (FNS) internal fixation. There were 6 males and 6 females with a median age of 52.5 years (range, 21-63 years). The fractures were caused by traffic accident in 2 cases, falling in 9 cases, and falling from height place in 1 case. All were unilateral closed femoral neck fractures, including 7 on the left side and 5 on the right side. The time from injury to operation was 1-11 days, with an average of 5.5 days. The fracture healing time and postoperative complications were recorded. The quality of fracture reduction was evaluated by Garden index. At last follow-up, Harris score was used to evaluate the hip joint function, also the shortening of femoral neck was measured. All the operations were successfully completed. After operation, the incision fat liquefaction occurred in 1 case, which healed after enhanced dressing change, and the other patients' incisions healed by first intention. All patients were followed up 6-18 months, with an average of 11.7 months. The X-ray film reexamination showed that the quality of fracture reduction was grade Ⅰ in 10 cases and grade Ⅱ in 2 cases according to the Garden index. All fractures reached bony union, and the healing time was 3-6 months, with an average of 4.8 months. At last follow-up, the femoral neck was shortened by 1-4 mm, with an average of 2.1 mm. No internal fixation failure or osteonecrosis of the femoral head occurred during follow-up. At last follow-up, the hip Harris score was 85-96, with an average of 92.4; 10 cases were rated as excellent and 2 were good. The percutaneous screwdriver rod-assisted closed reduction can effectively reduce the valgus-impacted femoral neck fracture. It has the advantages of simple operation, effective, and less impact on blood supply.

"In-Out-In" Percutaneous Reduction Technique for Treatment of Valgus-Impacted Femoral Neck Fractures: A Technical Trick and Case Series.

Valgus-impacted femoral neck fractures with or without posterior tilt of the femoral head are very common and full of pitfalls in clinical practice, which may lead to femoral neck shortening (FNS) and avascular necrosis (AVN). The study tries to introduce a novel technical trick aiming at anatomical reduction of valgus-impacted femoral neck fracture with minimally invasive procedure, and summarize the clinical prognosis in case series. In this retrospective study, 24 patients (seven men and 17 women) with valgus-impacted femoral neck fractures between May 2017 and July 2020 were managed by "in-out-in" percutaneous reduction technique (percutaneous reduction group). Another 24 cases (10 men and 14 women) suffering the fractures underwent in situ fixation were enrolled as control group for function comparison (in situ fixation group). All patients were followed up for 24-42months. The clinical outcomes included complications after operations (χ2 test) and Harris Hip Score (HHS) for hip function (unpaired t test) in the two groups. The radiographic outcomes were evaluated by collodiaphyseal angle, posterior tilt angle, and FNS before the operation and during the follow-up in the percutaneous reduction group (unpaired t test). Patients' preoperative data, including age, sex, affected side, fracture types, and medical history, were similar between the two groups, respectively (p > 0.05). After surgery, the mean HHS at 6, 12, and 24months were all better in the percutaneous reduction group (76 ± 6.72, 85.34 ± 6.33 and 90.54 ± 5.81) than that in the in situ fixation group (70.86 ± 6.91, 80 ± 6.11 and 84.1 ± 7.82), respectively (p < 0.05). One patient suffered fixation failure with screws retreat and one patient suffered AVN in the percutaneous reduction group. In the in situ fixation group, AVN occurred in two patients at last follow-up. There was no significant difference in complication amounts between the two groups (p > 0.05). In the percutaneous reduction group, collodiaphyseal angle, posterior tilt angle, and amount of FNS were significantly different between preoperative cases and immediately postoperative cases (p < 0.05). However, there was no statistical difference of the measurements among postoperative cases at different time points (within 24h, 6 months, and 2 years postoperatively) (p > 0.05). Our experience of the technique and the case series show that "in-out-in" percutaneous reduction technique for treatment of valgus-impacted femoral neck fracture with or without posterior tilt of the femoral head is safe and effective for achieving successful bone union and satisfactory function.

Finite element analysis of necessity of reduction and selection of internal fixation for valgus-impacted femoral neck fracture

This study compared the biomechanical characteristics of different treatment strategies based on finite element analysis. Posterior tilt and valgus angle were measured on X-ray from ten valgus-impacted femoral neck fractures, and 7 finite element models that were generated to compare the stress and displacement. The results showed that in the intact femur, von Mises stress was concentrated at the medial and inferior sides of the femoral neck. In valgus-impacted femoral neck fractures, von Mises stress was at the same locations but was 5.66 times higher than that in the intact femur. When 3 cannulated screws were used for internal fixation, anatomic reduction diminished the stress at the fracture end from 140.6 to 59.14 MPa, although displacement increased from 0.228 to 0.450 mm. When the fracture was fixed with a sliding hip screw (SHS) + cannulated screw, there was less stress at the fracture end and greater displacement with anatomic reduction than that without reduction (stress: 15.9 vs 37.9 MPa; displacement: 0.329 vs 0.168 mm). Therefore, the SHS + cannulated screw has superior biomechanical stability than 3 cannulated screws, and is recommended following anatomic reduction to treat valgus-compacted femoral neck fractures.

Valgus Impacted Femoral Neck Fractures: Surgery or Non-Operative Approach?

Background: Non-operative management of valgus impacted femoral neck fracture leads to prolonged bed rest which may lead to deep vein thrombosis. The preferred method is the internal fixation because of pain control, enhanced mobilization, and better fracture healing but fails in older patients and individuals with medical comorbidities. The present study aims to assess the functional outcomes after the internal fixation or the non-operative management. Methods: A retrospective cohort study was conducted at a Level I trauma center from January 2013 to December 2019 on all patients with valgus-impacted femoral neck fractures [Arbeitsgemeinschaft für Osteosynthesefragen/Orthopedic Trauma Association Classification (AO/OTA 31-B1)]. Overall, 81 patients were managed operatively with three partially threaded, cannulated screws in a parallel configuration and 21 patients were managed non operatively with instant mobilization, physical therapy, and partial weight-bearing protocol. Results: 6 (28.0%) patients in the non-operative group and 3 (4.0%) cases in the operative group experienced fracture displacement (P &lt; 0.001). 48 (59.2%) patients of the operative treatment group returned to baseline ambulatory function at 3 months, while this figure was 43.0% in the non-operative treatment group, not significantly different (P = 0.100). There was no significant difference in the mortality rates at one month and three months between the two groups (2 patients in each group, P = 0.140). Conclusion: The ideal treatment of valgus-impacted femoral neck fractures is still controversial. The main purpose in the treatment of hip fractures is to return the patient to functional level equal to the level he or she was before the fracture. Surgically treated patients had lower failure rates in comparison with the other group.

Incidence and risk factors for failure of conservative treatment for valgus impacted femoral neck fractures in elderly patients with high-risk comorbidities–A bi-center retrospective observational study

Background–Establishing the ideal indications for conservative treatment for elderly patients with valgus impacted femoral neck fractures is difficult because few studies have identified predictive factors for the failure of this treatment method. This study aimed to report the outcomes of conservative treatment for elderly patients with valgus impacted femoral neck fractures and determine risk factors that lead to treatment failure. Methods–From January 2009 to December 2018, 206 patients with valgus impacted femoral neck fracture were identified at two institutions. Elderly patients with valgus impacted femoral neck fractures corresponding to an Orthopedic Trauma Association/AO Foundation (OTA/AO) classification of 31-B1.1 or 31-B1.2 who were treated conservatively were included in the study. The following data was collected to compare the preoperative characteristics of patients with valgus impacted femoral neck fractures: age, sex, bone mineral density, medical comorbidities (hypertension, diabetes mellitus, ischemic heart disease, arrhythmia, chronic kidney disease [CKD], and stroke), medial cortex displacement, valgus angle, posterior tilt, and retroversion. These data were used to assess the independent predictors for failure of conservative treatment using multiple logistic regression analysis. Results–The failure rate after conservative treatment for valgus impacted femoral neck fracture in the enrolled patient group was 27.3% (15 of 55). CKD, presence of medial cortex displacement, high posterior tilt, and high retroversion were all identified as independent predictors for failure. The cut-off values for retroversion and posterior tilt that predicted treatment failure were 12.5° (area under curve [AUC] 0.768, p = 0.002, 95% confidence interval [CI] 0.632–0.903, sensitivity 0.733, 1-specificity 0.300) and 7.5° (AUC 0.712, p = 0.016, 95% CI 0.542- 0.881, sensitivity 0.667, 1-specificity 0.325), respectively. Conclusions–The present study showed that a high union rate could be obtained if the indications for conservative treatment in for elderly patients with valgus impacted femoral neck fractures are well-defined. Thus, we believe that conservative treatment can be a viable option for valgus impacted femoral neck fractures when elderly patients with high-risk comorbidities have acceptable fracture angulation, no medial cortex displacement, and no CKD. Level of Evidence–Level III, retrospective cohort study.

A finite element analysis study based on valgus impacted femoral neck fracture under diverse stances

The aim of the study was to determine the biomechanical environment of patients who suffer from valgus impacted femoral neck fracture. With the help of computational modeling, both of finite element hip fracture and normal three-dimensional model were reconstructed from a patient with hip fracture. The predicted stress distribution was compared between before and after fracture. After the fracture, during standing and the gait, the fracture site has a greater change in stress distribution due to the shortening of the femoral neck. The largest stress occurs at the middle and lower end of the femoral shaft, which occurs from toe off to deceleration during the whole gait. After the fracture, greater stress on the femoral head will result in a worse mechanical environment for the femur. The stress peak value of the femoral shaft is larger than the unfractured side and the stress distribution is uneven. From the results of gait analysis, it is concluded that the increase of concentrated stress and the change of stress distribution will cause the possibility of secondary fractures at the middle and lower ends of the femoral shaft when there is an accident in the case of existing fracture.

Clinical outcome of valgus impacted femoral neck fractures treated by closed reduction and fixation

Clinical outcome of valgus impacted femoral neck fractures treated by closed reduction and fixation

Comparison of femoral neck shortening and outcomes between in situ fixation and fixation after reduction for severe valgus-impacted femoral neck fractures

IntroductionSevere valgus-impacted femoral neck fractures are associated with femoral neck shortening (FNS). However, no study has focused on the effect of reduction for severe valgus impaction in terms of healing and restoration of the femoral neck length. This study aimed to compare FNS and treatment outcomes of in situ fixation and fixation after reduction for severe valgus-impacted femoral neck fractures in patients aged 65 years or younger. MethodsThis retrospective study included 55 patients who underwent internal fixation with three parallel screws for femoral neck fractures with valgus impaction >15° (AO/OTA classification 31-B1.1) between January 2006 and December 2018. Twenty-eight and 27 patients underwent in situ fixation (in situ group) and fixation after reduction (reduction group), respectively. In the reduction group, reduction using lateral traction with a Schanz pin was performed before internal fixation. Complications such as fixation failure, non-union, and avascular necrosis (AVN), caput-collum-diaphysis (CCD) angle, posterior tilt angle, amount of FNS, and Harris Hip Score (HHS) were compared between the groups. ResultsBone union was achieved in all patients; AVN occurred in two patients in each group. No significant difference was seen in the preoperative characteristics between the groups. The CCD angle at 1 year postoperatively was significantly different between the groups, whereas the posterior tilt angle at 1 year postoperatively was not different. FNS at 1 year postoperatively was significantly lower in the reduction group than in the in situ group. FNS by >5 mm was significantly less frequent in the reduction group than in the in situ group (11% versus 75%). The mean HHS at 1 year and 2 years postoperatively was significantly higher in the reduction group than in the in situ group. FNS and HHS were negatively correlated; the mean HHS was significantly higher in patients with none/mild shortening (<5 mm) than in those with moderate/severe shortening (≥5 mm). ConclusionIn patients aged 65 years or younger, internal fixation after reduction for severe valgus-impacted femoral neck fractures is safe and effective for achieving successful bone union and restoring the femoral neck length.

Is percutaneous screw fixation really superior to non-operative management after valgus-impacted femoral neck fracture: a retrospective cohort study.

The optimal management of valgus-impacted femoral neck fractures remains controversial. Internal fixation is associated with significant rates of re-operation, while historical non-operative management strategies consisting of prolonged bed rest also resulted in patient morbidity. Our hypothesis was that screw fixation would have comparable failure rates to non-operative treatment and immediate mobilization for valgus-impacted femoral neck fractures. Retrospective cohort at a single academic Level I trauma center of patients with valgus-impacted femoral neck fractures (AO/OTA 31-B1) treated with percutaneous screw fixation (n = 97) or non-operatively (n = 28). Operative treatment consisted of percutaneous screw fixation. Non-operative treatment consisted of early mobilization. The primary outcome was a salvage operation. Patient demographics were assessed between groups. More non-operatively treated patients were permitted unrestricted weight-bearing (WBAT; p = 0.002). There was no increase in complication rates or mortality, and return to previous ambulatory status was comparable between operatively and non-operatively treated patients. 35.7% (10/28) of non-operatively treated patients underwent a subsequent operation, compared to 15.5% (15/97) of patients with screw fixation (p = 0.03). Only WBAT was independently associated with treatment failure (OR 3.1, 95%CI 1.2-8.3, p =0.02). WBAT was predictive of treatment failure only in the non-operatively treated group (64.3%, 9/14 WBAT vs 8.3%, 1/12 partial, p =0.005). After controlling for weight-bearing restrictions, we found no difference in failure rates between non-operative treatment and screw fixation. Non-operative treatment with partial weight-bearing had low failure rates, comparable complication and mortality rates, and equivalent functional outcomes to operative treatment and is reasonable if a patient would like to avoid surgery and accepts the risk of subsequent arthroplasty. Overall, there were relatively high failure rates in all groups.

A Simple Percutaneous Technique to Reduce Valgus-Impacted Femoral Neck Fractures.

The mainstream surgery for valgus-impacted femoral neck fractures (FNFs) is closed reduction and internal fixation under fluoroscopy. However, femoral neck shortening and anterior femoroacetabular impingement are common complications in healed valgus-impacted FNFs after in situ fixation. Some methods have been reported to prevent complications, but these techniques require the use of a transfixing guide wire that passes through the femoral head, which may cause articular cartilage damage. We introduce a simple reduction technique using one Steinmann pin (S-pin) for valgus-impacted FNFs without any interference of the femur head. A S-pin was placed percutaneously at the inferomedial margin of the fracture, and reduction was achieved by applying manual valgus force along the fracture line. By restoring the anatomical alignment, we confirmed the maximum contact area of the fracture and connection of the medial cortical buttress, so the risk of nonunion was also minimized.

Effect of Training Modules on Hip Fracture Surgical Skills Simulation Performance: Early Validation of the AAOS/OTA Simulator.

A preliminary validation study on a computer-based force-feedback simulation platform demonstrated the ability of the simulator to distinguish between novice and experienced users during a simulated hip-pinning procedure. The purpose of the present study was to further investigate whether the simulator and associated training modules are effective for improving user performance during simulated percutaneous hip-pinning procedures. With institutional review board approval, 24 medical students at our institution were randomized to "Trained" and "Untrained" groups. After a basic introduction, the Untrained group placed 3 guidewires in a valgus-impacted femoral neck fracture with use of the simulator. The Trained group completed 9 simulator-based training modules before performing the same task. Measured outcomes included an overall performance score and the distance from the pin to various ideals on the femoral neck, femoral head articular surface, and lateral cortex. Performance parameters were compared between groups with the Mann-Whitney U test. The Trained group achieved a significantly higher overall score (median, 29) compared with the Untrained group (median, 6) (p < 0.01), outperformed the Untrained group in 4 specific performance metrics, and trended toward improvement over the Untrained group in 4 pin placement measures (p < 0.2). Completion of novel training modules for percutaneous hip pinning on this fluoroscopic surgery simulator improves skill performance on simulator-based objective measurements and a simulated orthopaedic procedure compared with non-simulator-trained surgically inexperienced users. Improvement in the overall score and on 4 of 13 specific performance parameters implies that the training modules more effectively teach only certain motor and 3-dimensional spatial skills. A valid platform such as the one described here has the potential to improve surgical education in orthopaedic trauma.

Cross-Table Lateral Radiographs Accurately Predict Displacement in Valgus-Impacted Femoral Neck Fractures

Background:Femoral neck fractures are classified as nondisplaced (Garden types I and II) or displaced (Garden types III and IV) on the basis of anteroposterior radiographs. Cross-table lateral radiographs are important in the assessment of Garden type-I and II fractures as posterior tilt of the femoral head may influence treatment results. A posterior tilt of >20° has been associated with an increased risk of treatment failure after internal fixation, although the precision of these measurements has not been validated. Therefore, the purpose of the present study was to compare cross-table lateral radiographs with 3-dimensional computed tomographic (3D-CT) reconstructions of Garden type-I and II femoral neck fractures.Methods:Twenty-three patients presenting with Garden type-I and II femoral neck fractures that were verified on anteroposterior radiographs underwent CT scanning immediately after radiographic examination. 3D models of the fractured and uninjured femora were reconstructed from the CT images, and displacement of the 3D models was determined by superimposing the fractured and uninjured femora. We defined a coordinate system with its origin at the center of the uninjured femoral head with the x axis oriented medially; the y axis, posteriorly; and the z axis, cranially. Correlations between lateral radiographs and 3D models were assessed with the Spearman rank coefficient, mean difference, and limits of agreement.Results:Posterior tilt of the femoral head on lateral radiographs was strongly correlated with displacement of the femoral head along the y axis of the 3D models, with a correlation coefficient of 0.86 (p < 0.001). Correlations between the findings on lateral radiographs and displacements along the x or z axis were weak, with coefficients of −0.30 (p = 0.18) and 0.21 (p = 0.34), respectively. The mean difference between displacement on lateral radiographs and displacement along the y axis of the 3D models was smaller, and demonstrated a smaller limits-of-agreement interval, compared with the x or z axis.Conclusions:Our results demonstrated a strong correlation between posterior displacement of the femoral head on lateral radiographs and displacement along the y axis in 3D models of Garden type-I and II femoral neck fractures. This finding indicates that lateral radiographs provide an accurate assessment of posterior tilt.

Risk Factors for Neck Shortening in Patients with Valgus Impacted Femoral Neck Fractures Treated with Three Parallel Screws: Is Bone Density an Affecting Factor?

PurposeThe purpose of this study is to analyze the relationship between significant femoral neck shortening (SFNS) and bone density after three parallel screw fixation in valgus impacted femoral neck fracture, and to analyze the risk factors for SFNS.Materials and MethodsThis is retrospective study of 83 patients. We performed univariate analysis for patient information, bone density, fracture configuration and screw position divided into SFNS group (n=13) and non-SFNS group (n=70) and performed multivariate analysis using logistic regression model. We also analyzed the relationship between SFNS and complications such as osteonecrosis of femoral head and nonunion.ResultsThere was a significant difference in age, screw non-parallelism and bone mineral density of intertrochanteric and total hip area in the univariate analysis between the two groups (P<0.05). In multivariate analysis, old age (odds ratio [OR], 1.10; 95% confidence interval [CI], 1.03-1.21) and screw non-parallelism (OR, 2.95; 95% CI, 1.44-6.59) were significant risk factors for SFNS. The incidence of SFNS was significantly higher in the complication group (P=0.027).ConclusionBone density did not significantly affect SFNS in valgus impacted femoral neck fractures treated with three parallel screws. The risk factors of SFNS were old age and screw non-parallelism. Therefore, we recommend using other fixation method to prevent SFNS in older ages and making the screw position as parallel as possible when performing screw fixation in valgus impacted femoral neck fracture.

Rates and Risk Factors of Conversion Hip Arthroplasty After Closed Reduction Percutaneous Hip Pinning for Femoral Neck Fractures—A Population Analysis

BackgroundClosed reduction with percutaneous pinning (CRPP) for nondisplaced or valgus impacted femoral neck fractures is a relatively low-risk operation that can produce excellent union rates in some patients; however, failure can occur in selected patients requiring conversion to arthroplasty. The primary aim of this study was to perform a population-level analysis to determine the rate and timeframe of conversion from CRPP to total hip arthroplasty (THA) or hemiarthroplasty. MethodsThe PearlDiver database was queried from 2007-2015 for all patients who underwent CRPP for a femoral neck fracture. Survival analysis was used to evaluate the rate of conversion of CRPP to hemiarthroplasty or THA. Risk factors for conversion arthroplasty were identified using a multivariable cox proportional hazards model that included patient demographics and comorbidities. ResultsThere were 5122 patients in the Humana database and 4840 patients in the Medicare database that were included in analysis. At 5 years after CRPP, the conversion rate was 10.0% in the Medicare patients and 10.8% in the Humana patients. Risk factors for undergoing conversion from CRPP to arthroplasty in the Medicare cohort included preexisting diagnoses of pulmonary and/or circulatory comorbidities, peripheral vascular disease, hypertension, hypothyroidism, and metastatic cancer. In the Humana cohort, the only risk factors were male gender and acute blood loss anemia. ConclusionAlthough CRPP remains a successful operation in elderly patients and patients with certain comorbidities, failure of CRPP for the treatment of a femoral neck fracture is high at approximately 10%-11%, which is much higher than reported failure rates for THA in the same population. Patients with femoral neck fractures being considered for CRPP should be counseled about the possibility of further surgery.

The influence of the hips position on measurements of posterior tilt in a valgus-impacted femoral neck fracture

IntroductionLateral radiographs are important for the evaluation of Garden I and II femoral neck fractures. These fractures appear undisplaced in the anteroposterior view, but posterior tilt of the femoral head may still be present in the lateral view. The influence of posterior tilt is, however, debated, which could be caused by the use of non-standardized cross-table radiographs in the conflicting reports. The aim of this bone-model study was therefore to evaluate the influence of the hips position on measurements of posterior tilt. Materials and methodsWe generated models of a Garden I–II femoral neck fracture and the non-injured contralateral femur from CT reconstructions with a 3D-printer. Lateral radiographs of the models were obtained in positions ranging from 90° internal rotation (IR) to 90° external rotation (ER) and 0−80° flexion. Two investigators independently measured posterior tilt on 27 lateral radiographs obtained from each model. ResultsThe inter-tester ICC was 0.91 (0.84–0.94), standard error of measurement (SEM) 2.6, and minimal detectable change (MDC) 7.2. The median (range) posterior tilt for the fracture model was 21.9° (5.0, 33.8) and 23.6° (2.2, 28.6) for observer 1 and observer 2, respectively. The corresponding posterior tilt within the range of 10° IR to 40° ER and 0 to 30° flexion of the fracture model, was 27.3° (24.0, 33.8) and 26.3° (24.8, 28.6). DiscussionThe range of posterior tilt measurements for positions of the proximal femur restricted from 10° IR to 40° ER and 0 to 30° flexion, was above the MDC for observer 1, and below the MDC for observer 2. These findings indicate that rotation and flexion affect measurements of posterior tilt, but the influence may be negligible for positions of the injured extremity that are clinically relevant during cross-table lateral radiographs. A larger study that accounts for variations in anatomy and fracture displacement is required to confirm these findings.

Diminished abductor muscular strength in patients with valgus-impacted femoral neck fractures treated by internal fixation: Clinical study and biomechanical considerations.

Valgus-impacted femoral neck fractures treated with internal fixation occasionally result in unsatisfactory postoperative locomotive function, partially due to muscle shortening and a decrease in the moment arm. This study quantifies the degree of diminished abduction strength both clinically and biomechanically. Fifteen patients were enrolled in this study. Twelve patients with fracture healed in valgus-impacted position were further evaluated. Muscular strength around hip was examined, and values between the nonoperated and operated side were compared and analyzed. For the biomechanical study, two three-dimensional models were prepared: model I (control model without displacement) and model II (simulated malunion of a 15° valgus-impacted fracture). Two sets of hip flexion angles in each of the models were simulated with flexion angles of 0° and 23°. Mean and standard deviation values for muscle strength from the nonoperative/operative side among the valgus group are as follows: flexion strength was 9.2 ± 4.0/9.2 ± 3.2, extension strength was 5.8 ± 2.8/6.1 ± 3.2, abduction strength at 0° was 9.1 ± 3.7/7.4 ± 3.6, abduction strength at 10° was 6.7 ± 3.0/5.5 ± 2.2, and knee extension strength was 15.3 ± 6.2/15.1 ± 6.0 (kgf). When comparing values between the nonoperative and operative sides, statistical significance was only observed in abduction strength ( p < 0.01). The biomechanical models prove that valgus impaction decreases the moment arm by approximately 10% at both flexion angle. A significant decrease in abductor strength at 0° and 10° was observed in the valgus-healed group. This may be related to a decrease in the moment arm. Further research should be done to define the acceptable limit of deformity for the satisfactory postoperative functioning.

The Result of In Situ Pinning for Valgus Impacted Femoral Neck Fractures of Patients over 70 Years Old.

PurposeWe aimed to evaluate the outcome of fixation with cannulated screws for valgus impacted femoral neck fractures in patients over 70 years of age.Materials and MethodsWe reviewed the outcome in 33 patients older than 70 years with valgus impacted femoral neck fractures who were treated with cannulated screws fixation from May 2007 to December 2010. These patients were followed for at least a year. We assessed the fixation failure rate, body mass index (BMI), bone mineral density (BMD) of proximal femur, distance between screw tip and joint, number of screws and time from fracture to operation.ResultsWe identified six patients (18.2%) with failure. Two patients with subtrochanteric fractures through the screw insertion site and another patient with osteonecrosis were excluded from the fixation failure group. No difference was found in age, BMI, BMD of proximal femur, distance between screw tip and joint, number of screws and time from fracture to operation between failure and non-failure groups.ConclusionThe failure rate of cannualted screw fixation for valgus impacted femoral neck fractures in the elderly patients was not low. Risk of failure should be considered in the management of these patients and accurate assessment for fracture type should be performed using computed tomogram and clinical evaluation.