What features of stem increase the risk of intraoperative femoral fracture during cementless primary hip arthroplasty?

INTRODUCTION: Cementless fixation has become increasingly popular in hip arthroplasty due to its shorter operation time, easier technique, biologic fixation, and avoidance of bone cement implantation syndrome compared to cemented fixation. However, intraoperative periprosthetic femoral fracture (IOPFx) is a disconcerting complication during cementless hip arthroplasty. Our purpose was to identify the features of cementless stem that increase the risk of IOPFx during primary hip arthroplasty. MATERIALS AND METHODS: We retrospectively reviewed all 4806 hip arthroplasties that was performed in a single institution from May 2003 to December 2020. Age at the index arthroplasty, sex, body mass index, physical status, ambulatory function, side of the operation, operational history, cause of the index arthroplasty, type of arthroplasty, surgical approach, surgeon, implant information, and events during the operation were investigated. The shoulder geometry and length of stem were also reviewed. The event of interest was narrowed down to IOPFx among various records of intraoperative events. RESULTS: We found IOPFx of 2.6% among all the hips operated with cementless stem. In the multivariable analysis, female (OR = 1.52), childhood hip disease (OR = 2.30), stove-pipe femur (OR = 2.43), combined approach (OR = 2.60), and standard length of stem (OR = 1.59) were found to be significant risk factors of IOPFx. CONCLUSIONS: In conclusion, a stem with a standard length is significantly associated with risk of IOPFx compared to a shortened stem. These findings highlight the importance of careful consideration in terms of the risk of IOPFx when standard length cementless stem is chosen.

A Meta-Analysis of Polymerase Chain Reaction for Prosthetic Joint Infection Diagnosis.

BACKGROUND: One of the most dangerous side effects of joint replacement for the hip, knee, shoulder, and elbow is prosthesis joint infection (PJI). Polymerase chain reaction (PCR) has been considered a promising method for PJI diagnosis due to its short diagnostic time and high sensitivity. Although several PCR methods such as multiplex PCR and broad-range PCR are useful diagnostic methods for detecting microorganisms causing PJI, values of different PCR methods for the diagnosis of PJI remain unclear. Thus, the objective of this study was to perform a meta-analysis of different PCR methods in the diagnosis of PJI to determine their diagnostic characteristics including sensitivity and specificity. METHODS: The following data were extracted: PCR method, number of patients, sample site and type, diagnosis standard, true positive, false positive, false negative, and true negative. Pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were calculated. Meta-regression analysis was conducted to assess heterogeneity. Subgroup analysis was also performed to assess effects of several variables on meta-analysis results. RESULTS: The current study showed that pooled sensitivity and pooled specificity were 0.70 (95% CI: 0.67 - 0.73) and 0.94 (95% CI: 0.92 - 0.95), respectively. Results of subgroup analysis indicated that sequencing method showed the lowest sensitivity (0.63, 95% CI: 0.59 - 0.67). However, after excluding studies using tissue samples directly, sequencing method showed higher sensitivity (0.83, 95% CI: 0.73 - 0.90) than other PCR methods (0.74, 95% CI: 0.69 - 0.78). CONCLUSIONS: The main significance of this study was that we attempted to classify accuracies of several PCR methods and found that sequencing with a reliable sampling method could be used as an early screening strategy for PJI. Further comparisons for PCR technologies are needed to evaluate their cost effectiveness and diagnostic procedures, not just diagnostic values, to discover the optimal one for PJI diagnosis.

Pre-sliding of femoral neck system improves fixation stability in pauwels type III femoral neck fracture: a finite element analysis.

BACKGROUND: Femoral neck fractures are a common injury in older adults and their management presents a significant challenge for orthopedic surgeons. The Femoral Neck System (FNS) was recently introduced for the fixation of femur neck fractures. Although neck shortening was reduced with the FNS, the complication rates were not reduced. Thus, improvements to enhance fixation stability should be made for the FNS. We hypothesized that (1) the pre-sliding technique and (2) the use of longer anti-rotation screw would increase fracture stability. This study aimed to determine the change in fracture stability using the pre-sliding technique and long anti-rotation screw in the FNS for fixation of Pauwels type III femoral neck fractures. METHODS: Finite element models of Pauwels type III femoral neck fracture fixed with pre-sliding FNS and 5-mm longer anti-rotation screw were established. The models were subjected to normal walking load. The material properties of the elements belonging to the bone were mapped by assigning the formulation with the computed tomography Hounsfield unit. RESULTS: Pauwels type III femoral neck fractures fixed with pre-slided FNS showed better fracture stability, decreasing fracture gap and sliding by 14% and 12%, respectively, under normal walking load. No element of cortical bone in any of the models had an absolute value of principal strain that exceeded 1%. The peak von Mises stress (VMS) of the implants ranged from 260 to 289 MPa, and the highest peak VMS value was 50% lower than the yield strength of the titanium alloy (800 MPa). The longer anti-rotation screw did not affect fracture stability. CONCLUSIONS: The pre-sliding technique using the FNS showed higher fracture stability than the standard fixation technique for a Pauwels type III femoral neck fracture. The longer anti-rotation screw did not contribute significantly to fixation stability. As this finite element analysis considered the inhomogeneous mechanical property of the bone, it offered equivalent mechanical conditions to investigate the components of interest.

Trajectory of bolt and length of plate in femoral neck system determine the stability of femur neck fracture and risk of subsequent subtrochanteric fracture : a finite element analysis.

BACKGROUND: This study aimed to analyze the differences in the stability of fractures, stress distribution around the distal-most screw according to the length of the plate and the trajectory of the bolt in Pauwels type III femoral neck fracture using the femoral neck system (FNS). METHODS: Finite element models of Pauwels type III femoral neck fractures were established with surgical variations in the trajectory of the bolt (central, inferior, valgus, and varus) and length of the lateral plate (1- and 2-hole plate). The models were subsequently subjected to normal walking and stair-climbing loads. RESULTS: The screw-holding cortical bone in subtrochanter in the model with a 2-hole plate and the bolt in the inferior trajectory and the models with 1-hole or 2-hole plate and the bolt in valgus trajectory had shown greater maximum principal strain than the models with central or varus trajectories. The gap and sliding distance on the fracture surface were larger with inferior or varus trajectories of the bolt and smaller with the valgus trajectory of the bolt under both loads, compared to those of the central trajectory. CONCLUSION: For the fixation of Pauwels type III femoral neck fracture, the trajectory of the FNS bolt and the length of the plate affect the mechanical stability of the fracture and the strain of cortical bone around the distal-most screw. The surgical target should stay on the central trajectory of the bolt and the 2-hole plate's mechanical benefits did not exceed the risk.

Analysis of Changes in Sleep Quality and Patterns after Hip Fracture Using Real Evidence of Artificial Intelligence Linked (REAL) Hip Cohort Data.

Background and Objectives: Hip fractures are commonly found in elderly patients, and often result in chronic pain and decreased physical function, as well as worsening of overall health. It is known that early surgical intervention during the acute phase and rehabilitation are important for improving clinical outcomes for these patients. However, the importance of management for improving the quality of life of these patients is becoming more emphasized. Studies on changes in sleep patterns after hip fractures are rare overseas. Therefore, the aim of this study is to investigate the prevalence of sleep disturbance in patients with hip fractures and to analyze the changes in sleep disturbance after surgery by comparing the preoperative and postoperative results. Materials and Methods: During the period from August 2022 to January 2023, patients who underwent surgical treatment for hip fractures and were recruited into the REAL Hip Cohort were selected as research subjects. The sleep survey was conducted using the Pittsburgh Sleep Quality Index (PSQI). The PSQI is composed of 18 questions, each divided into areas of sleep quality, sleep latency, duration, efficiency, disturbance, use of medication, and daytime dysfunction. Each area is scored 0-3 points and the total is 0-21. A score greater than five indicates sleep disorder. The PSQI was surveyed during hospitalization and three months after surgery for post-fracture sleep status. To analyze changes before and after the fracture, paired T-tests and chi-square tests were performed. Results: From August 2022 to January 2023, a total of 40 patients who were recruited into the REAL Hip Cohort responded to the PSQI survey. The average age was 77.4 years and 36 were female. Sleep quality worsened from 0.75 ± 1.0 before surgery to 1.4 ± 1.0 three months after surgery (p = 0.019), and sleep efficiency also worsened from 0.4 ± 0.6 to 1.4 ± 1.0 (p < 0.001). The PSQI increased from an average of 5.2 ± 2.8 before surgery to 8.2 ± 4.2 three months after surgery (p = 0.007), and the number of patients who could be diagnosed with sleep disorders also increased from 12 (40%) to 24 (60%) (p = 0.030). Conclusions: A decline in overall sleep status was observed in patients in a survey on sleep patterns three months after hip fracture. Additional management is needed to improve their sleep patterns.

Association between antidepressants, benzodiazepine and all-cause mortality in elderly hip fracture: A Korean nationwide cohort study.

BACKGROUND: The purpose of this study was to analyze the association between the preoperative and postoperative use of antidepressant and benzodiazepine and all-cause mortality in elderly hip fracture patients. METHODS: Patients who underwent surgical treatment for hip fracture over 65 years old were classified into Past-user, Current-user, and Non-users for each period according to use history for antidepressants or benzodiazepines. And, for the subgroup analysis, patients were classified by presence of past history for psychiatric medication. A multivariable-adjusted Cox proportional hazards model was used to investigate the effects of antidepressants and benzodiazepines on all-cause mortality. RESULTS: A total of 15,576 patients were included in this study. Past users of antidepressants and benzodiazepines were 5699 (36.59%) patients and 11,319 (72.67%) patients, respectively. Current users of antidepressants and benzodiazepines were 2888 (18.54%) patients and 6287 (40.36%) patients, respectively. There were no statistically significant differences in the adjusted hazard for death compared to the non-users for both the past and the current users (p > 0.05). In the subgroup analysis, there were 12,502 once-users and 3074 never-users according to psychiatric medication. Current uses of antidepressants and benzodiazepine in the once-user did not increase adjusted hazard for death compared to the non-users (p>0.05). However, current uses of antidepressants by never-users increased the adjusted hazard for death compared to the non-user (adjusted hazard ratio, 1.31; 95% CI, 1.08-1.59; p = 0.007). CONCLUSIONS: No association was observed between the uses of antidepressants and benzodiazepines after hip fracture and mortality risk in elderly patients who received psychiatric medication before hip fracture. However, the use of these medications was associated with increased all-cause mortality risk in patients who had no history of psychiatric medication before hip fracture. LEVEL OF EVIDENCE: III, retrospective cohort study.

Improved control over implant anchorage under the use of the femoral neck system for fixation of femoral neck fractures: a technical note.

BACKGROUND: The depth of bolt in Femoral neck system (FNS, DePuy Synthes, Oberdorf, Switzerland) is difficult to finely control as the length of the bolt is in units of 5 mm. Thus, this study introduces a method to control the depth of FNS bolt in analogue scale in patients with femoral neck fracture. METHODS: By the technique of control of reaming and retraction of bolt, the tip of implant could be positioned close to subchondral bone without harming it. The position of implant tip in four cases in which the introduced technique was applied was compared to that of eight cases where the standard technique was performed. RESULTS: The average tip-apex distance measured in the cases that underwent surgery using the suggested technique in this study was statistically significantly shorter than that measured in the cases that underwent surgery under manufacturer guidelines. CONCLUSION: Even though the bolt of FNS is manufactured in the unit of 5 mm, the technique proposed in this study helps surgeons to adjust the depth of bolt for the fixation of femoral neck fracture using FNS.

Effect of Opioids on All-cause Mortality and Sustained Opioid Use in Elderly Patients with Hip Fracture: a Korea Nationwide Cohort Study.

BACKGROUND: The purpose of our study was to assess the use of opioids before and after hip fracture in elderly patients in order to determine the effect of opioid use on all-cause mortality, and to analyze how the history of opioid use before fracture increases the risk of sustained use following hip fracture using a Korea nationwide cohort. METHODS: Our study identified hip fracture patients from the Korean National Health Insurance Service-Senior cohort. The index date was defined as 90-days after admission to the acute care hospital that fulfilled the eligibility criteria of elderly hip fracture. Patients were classified into past user, current user, and sustained user according to the use of opioid at each period based on the time of admission and index date. The opioids were classified into strong opioids and tramadol. A generalized estimating equation model with a Poisson distribution and logarithmic link function was performed to estimate the adjusted rate ratios (aRRs) and 95% confidence intervals (CIs) to assess the association between past use and sustained use. A multivariable-adjusted Cox proportional hazard model was used to investigate the effects of strong opioid and tramadol use on all-cause mortality. RESULTS: A total of 12,927 patients were included in our study. There were 7,384 (57.12%) opioid past-users, 11,467 (88.71%) opioid current-users, and 7,172 (55.48%) sustained users. In comparison of the death risk according to current use or the defined daily dose of the opioids or past opioid use, there were no significant differences in the adjusted hazard ratio for death in all groups, compared to the current non-users (P > 0.05). Among survivors 1 year after hip fracture, opioid past-use increased the risk of opioid sustained use by 1.52-fold (aRR; 95% CI, 1.45-1.8; P < 0.001). CONCLUSION: Current use and past use of opioid did not increase all-cause mortality after hip fracture in elderly patients over 65 years of age. Past use of opioid before hip fracture increased risk of sustained use of opioid compared to the current opioid used without past use.

Disadvantage during Perioperative Period of Total Hip Arthroplasty Using the Direct Anterior Approach: a Network Meta-Analysis.

BACKGROUND: The purpose of this study was to analyze complications of complete hip arthroplasty through systematic review and network meta-analysis of comparative studies of direct anterior approach (DAA), anterolateral approach (LA), and posterolateral approach (PA). METHODS: Prospective randomized controlled trials (RCTs) or quasi-experimental designs evaluating clinical outcomes of DAA, LA, and PA for complete hip arthroplasty are valid if they meet the following criteria: 1) Comparison of clinical outcomes between the three methods for main complete hip arthroplasty (total hip arthroplasty, THA); 2) Compared at least one of the following outcomes: blood loss, operating time, and transfusion volume; 3) Sufficient data were available to extract and pool, i.e., mean reported, standard deviation and number of subjects. A network meta-analysis was used to determine the results of treatment across various surgical approaches. Indirect comparisons between the two surgical approaches was made by borrowing details from the standard comparator (i.e., the posterior approach). RESULTS: Eight prospective RCTs were included in the meta-analysis of the network. The operation time of the LA was longer than that of PA (standardized mean difference [SMD], 0.96; 95% confidence interval [CI], 0.74-1.18; P < 0.001). DAA also had significantly longer operation time than PA (SMD, 0.45; 95% CI, 0.24-0.66; P < 0.001). However, blood loss of the DAA was the highest compared to other approaches (SMD, 0.60; 95% CI, 0.39-0.82; P = 0.002). CONCLUSION: When performing THA with DAA, we should pay attention to increased operation time and blood loss.

Effect of Pneumonia on All-cause Mortality after Elderly Hip Fracture: a Korean Nationwide Cohort Study.

BACKGROUND: The purposes of this study were 1) to investigate the incidence of pneumonia during hospitalization in elderly hip fracture patients, 2) to evaluate the effect of pneumonia on 30 day to 1 year mortality and 3) to analyze the impact of age and gender on the mortality rate in the pneumonia patients using a nationwide cohort of Korea. METHODS: The Korean National Health Insurance Service (NHIS) database included approximately 5.5 million Korean enrollees > 60 years of age. A total of 588,147 participants were randomly selected for senior cohort using 10% simple random sampling. We identified senile (> 65 years old) patients who underwent hip fracture surgery from January 2005 to December 2014 and those who developed pneumonia during hospitalization from the NHIS-Senior cohort. The index date of hip fracture occurrence was defined as the date of admission to the acute care hospital. The last date of follow-up was defined as the date of death or 31 December 2015, whichever came first. A multivariable-adjusted Cox proportional hazards model was used to investigate the effects of pneumonia on all-cause mortality. RESULTS: During the enrollment period, a total of 14,736 patients, who were older than 65 years, underwent hip fracture surgeries. Among them, 1,629 patients (11.05%) developed pneumonia during the hospitalization. The pneumonia incidence was 16.39% (601/3,666) in men patients and 9.29% (1,028/10,042) in women patients. Compared to 13,107 non-pneumonia patients, adjusted relative risk (aRR) of death in pneumonia patients was 2.69 (95% confidence interval [CI], 2.14-3.38; P < 0.001) within postoperative 30-day, 3.40 (95% CI, 3.01-3.83; P < 0.001) within postoperative 90-day, 2.86 (95% CI, 2.61-3.15; P < 0.001) within postoperative 180-day and 2.31 (95% CI, 2.14-2.50; P < 0.001) within postoperative 1-year. According to patient's age, the aRR of death in pneumonia patients was 5.75 (95% CI, 2.89-11.43) in adults aged < 70 years, 5.14 (95% CI, 4.08-6.46) in those aged 70-79 years, 3.29 (95% CI, 2.81-3.86) in those aged 80-89 years and 2.02 (95% CI, 1.52-2.69) in those aged ≥ 90 years. The aRR was 3.63 (95% CI, 3.01-4.38) in men pneumonia patients, and 3.27 (95% CI, 2.80-3.83) in women pneumonia patients. CONCLUSION: The prevalence of pneumonia in elderly hip fracture patients was 11.05%. Men had higher incidence (16.39%) than women (9.29%). Compared to non-pneumonia patients, the pneumonia patients had higher 30-day to 1-year mortalities with aRR of 2.31 to 3.40. They had increased mortality in all age groups older than 65 years with aRR of 1.52 to 4.08. Both genders of pneumonia patients had higher risk of mortality (aRR, 3.63 in men and 3.27 in women) compared to non-pneumonia patients.

Blood Transfusion for Elderly Patients with Hip Fracture: a Nationwide Cohort Study.

BACKGROUND: This nationwide study aimed to investigate the blood transfusion status of elderly hip fracture patients and to examine the effect of packed red blood cell transfusion on all-cause mortality. METHODS: From the Korean National Health Insurance Service-Senior cohort consisting of 588,147 participants aged over 60 years in 2002, a total of 14,744 new-onset hip fracture patients aged 65-99 years were followed up for 11 years. The adjusted hazard ratios (aHRs), risk ratios, and their 95% confidence intervals were estimated by the Cox proportional hazard model and Poisson regression model. RESULTS: There were 10,973 patients (74.42%) in the transfusion group and 3,771 (25.58%) patients in the non-transfusion group. The mean volume of blood transfusion was 1,164.51 mL (± 865.25; median, 800 mL; interquartile range, 640-1,440). In the multivariable-adjusted Cox proportional hazard model, the transfusion group had 1.34-fold more risk of all-cause mortality than the non-transfusion group (aHR, 1.34; 95% confidence interval [CI], 1.26-1.42). In the multivariate-adjusted Poisson regression model, hip fracture patients in the transfusion group were 1.43 (adjusted risk ratio [aRR], 1.43; 95% CI, 1.09-1.87; P = 0.009) folds more likely to die within 30 days than those in the non-transfusion group. The mortality risk was highest at 90 days (aRR, 1.64; 95% CI, 1.40-1.93; P < 0.001) and slightly decreased at 180 days (aRR, 1.58; 95% CI, 1.40-1.79; P < 0.001) and 1 year (aRR, 1.43; 95% CI, 1.31-1.58; P < 0.001). CONCLUSION: In this nationwide representative cohort study, blood transfusion was performed in 75% of hip fracture patients. Even after adjusting for comorbidity and anticoagulant use, the postoperative results (hospitalization, mortality) of the transfusion group did not show significantly worse results than the non-transfusion group. Therefore, adequate patient blood management can only improve the patient's outcome after hip fracture surgery.

Total Hip Arthroplasty With Trochanteric Ostectomy for Patients With Angular Deformity of the Proximal Femur.

BACKGROUND: Total hip arthroplasty (THA) of patients with a proximal femoral deformity is technically demanding. This deformity poses the risk of femoral fracture or perforation; stem malposition; and failed stem fixation. To insert a femoral stem in neutral position with a good fit, we removed the greater trochanter in case of a varus deformity, and the lesser trochanter in case of valgus deformity, while performing THA. We aimed to evaluate stem position, implant stability, clinical results, and radiological changes after THAs using this technique. METHODS: Fifteen patients (17 hips; 11 varus hips and 6 valgus hips) underwent cementless THA using the trochanteric osteotomy technique in one institution. We evaluated procedure-specific complications: intraoperative femoral fracture, stem malposition, weakness of the abductor power and limp. Modified Harris Hip Score, radiological changes, and the stability of stems were assessed at a mean of 7.1 years of follow-up (range 2.0-15.5). RESULTS: Femoral fracture occurred during the insertion of the stem in 4 hips. All stems were aligned in neutral position. At the latest follow-up, the mean power of the abductor was 4.3 (range 3-5). Eleven patients had slight limp and 4 patients had moderate limp. All stems had bone-ingrown stability and no stem was revised. The mean modified Harris Hip Score improved from 50 points at the preoperative evaluation to 81 points at the final follow-up. CONCLUSION: The trochanteric excision enabled neutral insertion of cementless stem in patients with varus/valgus deformity of the proximal femur, and THA using this technique rendered favorable results.

Single screw type of lag screw results higher reoperation rate in the osteosynthesis of basicervical hip fracture.

BACKGROUND: Basicervical hip fractures are relatively rare with greater biomechanical instability compared to the other types of hip fractures. Several studies have reported ambivalent surgical outcomes of basicervical hip fractures. The purpose of this multicenter study was to analyze surgical outcomes of basicervical hip fractures according to the fixation type of proximal femur and lag screw type. METHODS: Among 3220 hip fractures, 145 were classified as basicervical hip fractures. Of those, 106 patients treated with osteosynthesis were included to analyze the surgical complications according to fixation type of proximal femur: sliding hip screw(SHS) and cephalomedullary nail (CMN) groups. Surgical complications including the excessive displacement of fracture and the occurrence of reoperation were evaluated at the final follow up. We further evaluated surgical complications according to lag screw type with subgroup analysis in CMN group: single screw type, blade type and two integrated screw type. RESULTS: Ten patients (9.4%) sustained surgical complications (5 excessive displacements and 5 reoperations). For fixation type of proximal femur, SHS group showed higher tendency of excessive displacement despite no statistical difference between the two groups (p = 0.060). For lag screw type with subgroup analysis in CMN group, single screw type showed statistically high rates of reoperation compared to the other types of lag screw (p = 0.022). CONCLUSION: Basicervical hip fractures treated with osteosynthesis resulted to high rates of surgical complications in this study. However, they could be drastically reduced if CMN with blade type or two integrated screw type were used in the osteosynthesis of basicervical hip fractures.

Comparison of intraoperative radiation exposure with and without use of distal targeting device: a randomized control study.

INTRODUCTION: When locking intramedullary nails, inserting the distal interlocking screw accurately and quickly with less radiation exposure is very important. The purpose of this randomized control study was to compare radiation exposure and accuracy of distal locking screws between free-hand fluoroscopic guidance and the use of a distal targeting system (DTS). MATERIALS AND METHODS: Inclusion criteria of this study were patients older than 60 years who need an intramedullary nailing due to unstable intertrochanteric and subtrochanteric fracture. The primary outcome was the attempt numbers of image intensifier during the insertion of distal locking screws. Secondary outcomes were operative time and angles between distal locking screws and nail. RESULTS: A total of 36 patients participated in the study. Eighteen patients using free-hand fluoroscopic guidance were assigned to Group I while 18 patients using DTS were assigned to Group II. The number of attempts of image intensifier during distal screw insertion (57.3 ± 31.42 vs. 11.5 ± 7.41, p < 0.001), ratio of attempt number for distal screws to the total attempts (0.33 ± 0.21 vs. 0.12 ± 0.08, p = 0.001), the number of hand exposure to image intensifier directly (75.0 ± 29.55 vs. 13.5 ± 19.07, p < 0.001), and the time of radiation exposure during distal screws insertion (42.57 ± 2.42 s vs. 12.72 ± 8.10 s, p < 0.001) were significantly lower in Group II compared to those in Group I. And, operation time (96.3 min ± 18.94 vs. 76.1 min ± 14.10, p < 0.001) was also statistically significantly lower in Group II. Both distal locking screws were significantly closer to perpendicular direction to the nail in Group II. CONCLUSION: The attempt number of image intensifier during the insertion of two distal locking screws was significantly reduced with DTS compared with that with free hand fluoroscopic guidance. Angle between distal locking screws and nail was also more accurate using DTS.

Morphological Patterns of Anterior Femoral Condylar Resection in Kinematically and Mechanically Aligned Total Knee Arthroplasty.

BACKGROUND: "Grand-piano sign" has been used as a popular benchmark to facilitate correct rotational alignment during total knee arthroplasty (TKA). The purpose was to quantitatively determine morphological patterns on anterior femoral resection in mechanically aligned (MA) and kinematically aligned (KA) TKA. METHODS: Computed tomography scans of 60 TKA candidates were reconstructed into 3D models. Femurs were virtually cut with a 3D imaging program using various anterior flange flexion angles (AFFAs) of 3°, 5°, and 7°. The anterior femoral resection was performed parallel to the surgical epicondylar axis, at an external rotation and internal rotation of 3° relative to surgical epicondylar axis for MA-TKA, and parallel to the cylindrical axis, at an external rotation and internal rotation of 3° to cylindrical axis for KA-TKA. The ratio of vertical distance from the anterior margin of distal femoral resection to the most proximal peak of each medial and lateral condyle of anterior femoral resection was defined as AC/BC ratio. RESULTS: The mean ratios of AC/BC were 0.57, 0.60, and 0.63 respectively, according to 3°, 5°, and 7° of AFFA with standard MA-TKA method and were 0.73, 0.74, and 0.76, respectively, according to 3°, 5°, and 7° of AFFA with standard KA-TKA method. The AC/BC ratios of malrotated planes were significantly different from those of both standard MA- and KA-TKAs (P-values < .01). CONCLUSION: Surgeons can accessorily use the quantifying method for anterior femoral resection intraoperatively to ensure correct rotational alignment of femoral resection in both mechanically and kinematically aligned TKA.

Mid-Term Survivals After Cementless Bipolar Hemiarthroplasty for Unstable Intertrochanteric Fractures in Elderly Patients.

BACKGROUND: Treatment of unstable intertrochanteric fracture in elderly patients remains challenging. The purpose of this prospective study is to determine clinical and radiological results of cementless bipolar hemiarthroplasty using a fully porous-coated stem in osteoporotic elderly patients with unstable intertrochanteric fractures with follow-up over 5 years. METHODS: From January 2010 to December 2011, we performed 123 cementless bipolar hemiarthroplasties using fully porous-coated stem to treat unstable intertrochanteric fractures in elderly patients with osteoporosis. Clinical and radiographic evaluations were performed. RESULTS: Fifty-three patients died and 14 patients were lost during the follow-up period. Mean follow-up period was 61.8 months postoperatively. Their mean Harris hip score was 77 points (range 36-100). None of these hips had loosening of the stem or osteolysis. Postoperative complications included nonunion of greater trochanter in 2 hips and dislocation in 2 hips. Two patients were reoperated due to periprosthetic fracture. One patient underwent implant revision due to periprosthetic infection. Thirty-one patients maintained walking activities similar to those before fracture. With follow-up period of 83 months, cumulative survival rates were 97.3% and 99.1% with reoperation for any reason and femoral stem revision as endpoint, respectively. CONCLUSION: Cementless bipolar hemiarthroplasty using a fully porous-coated stem is a useful surgical treatment option for unstable intertrochanteric fracture in elderly patients with osteoporosis.

What is the tolerated width of periacetabular osteophytes to avoid impingement in cementless THA?: a three-dimensional simulation study.

BACKGROUNDS: Impingement is a risk factor for instability and prosthetic failure following total hip arthroplasty (THA). If the periacetabular osteophytes are not removed at surgery, impingement could occur between the osteophytes and the femoral stem following THA. However, excessive removal of the osteophytes could lead to bleeding from the bone. The aim of our study, therefore, was to locate the site of the impingement and to determine the width of tolerable osteophytes, which does not induce impingement during activities of daily living (ADL), using a three-dimensional simulation. METHODS: On 35 hip models, virtual THA was performed. The acetabular cups were positioned at 45° abduction and 20° anteversion, and the anteversion of femoral stems was 15°. Circular osteophytes with a 30-mm rim were built around the acetabular cup. Fourteen ADL motions were simulated, and the osteophytes were removed until there was no impingement. A clock face was used to map the location and the width of tolerable osteophytes. RESULTS: The impingement mainly occurred in antero-superior and posterior portions around the acetabular cup. Only 4.2-6.2-mm osteophytes were tolerable at the antero-superior portion (12-3 o'clock) and 6.3-7.2-mm osteophytes at the posterior portion (8-10 o'clock) following a total hip arthroplasty. In antero-inferior and postero-superior portions, over-20-mm osteophytes did not induce any impingement. CONCLUSION: Osteophytes in the antero-superior and posterior portion of the acetabulum should be excised during a THA to avoid impingement of the femur-stem construct on the acetabular osteophytes during ADLs.

Conservative Treatment for Minimally Displaced Type B Periprosthetic Femoral Fractures.

BACKGROUND: Surgical treatment has been invariably indicated for Vancouver type B periprosthetic femoral fractures (PFFs), which involve femoral diaphysis around stem. We evaluated the outcomes of nonoperative management in patients with minimally displaced type B PFFs around cementless stem. METHODS: From October 2009 to March 2016, 60 type B PFFs were treated at 1 institution. Among them, 19 minimally (<5 mm) displaced PFFs (31.7%, 19/60), which occurred around cementless stems, were treated nonsurgically with use of teriparatide. There were 6 men and 13 women. The mean age was 77.9 years (range, 51-98 years) at the time of PFF. The femoral stem was stable (type B1) in 11 patients and unstable (type B2) in 8. Teriparatide was injected from 1 to 4 months (mean, 3.2 months). We evaluated time to radiologic union and union rate. RESULTS: A successful union was obtained in 16 patients (89.5%, 17/19) at 2 to 6 months (mean, 3.5 months). The union rate was 100% (11/11) in type B1 fractures and 75% (6/8) in type B2 fractures. CONCLUSION: Our study showed that conservative treatment is feasible for the cases of type B1 minimally displaced periprosthetic fractures, and it may also be considered as an alternative option for type B2 minimally displaced periprosthetic fractures.

Conversion Hip Arthroplasty in Failed Fixation of Intertrochanteric Fracture: A Propensity Score Matching Study.

BACKGROUND: Conversion hip arthroplasty is a salvage procedure for failed internal fixation of intertrochanteric fractures. However, the technical difficulties and perioperative morbidity of conversion arthroplasty are uncertain. METHODS: We compared the type of arthroplasty (total hip arthroplasty or hemiarthroplasty), operative parameters, perioperative morbidity, 1-year mortality, implant stability, and clinical results of 33 conversion hip arthroplasties due to a failed internal fixation of intertrochanteric fracture with those of a matched control group of 33 primary hip arthroplasties due to the same fracture. Propensity score was used for the control matching of gender, age, and body mass index. RESULTS: Total hip arthroplasty was more frequently performed in the conversion group (10/33) compared to the primary group (3/33) (P = .016). The operation time, perioperative blood loss, amount of transfusion, and risk of femoral fracture during the operation were increased in the conversion group. The overall 1-year mortality was 3% (1 patient) in the conversion group and 9% (3 patients) in the primary group (P = .307). At a mean of 3-year follow-up, there was no significant difference in clinical results and none of the implants were loose in both groups. CONCLUSION: In patients with failed internal fixation of intertrochanteric fracture, conversion hip arthroplasty should be planned and executed, bearing in mind the increased operative morbidities corresponding to operation time, perioperative blood loss, requirement of transfusion, and intraoperative femoral fracture.