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Background: Perioperative greater trochanteric fracture following total hip arthroplasty (THA) using the anterolateral approach is a recognized perioperative complication. There was no previous study to determine the relationship between bone mineral density (BMD) and three-dimensional greater trochanter morphology for perioperative greater trochanter fractures. The purpose of this study is to identify the influence of greater trochanteric bone density and three-dimensional morphology on perioperative greater trochanteric fracture following THA using the anterolateral approach. Methods: We investigated 209 hips done primary THA using the anterolateral approach and preoperative BMD test for the proximal femoral bone with a minimum of 6 months follow-up. We picked up all patients who had perioperative greater trochanteric fractures. Multivariate analysis was done in order to investigate the influence of the greater trochanter young adult mean (YAM) and three-dimensional morphology on perioperative greater trochanteric fractures. Results: There were 10 joints (10/209, 4.8%) with perioperative greater trochanteric fractures. Osteosynthesis was required only in one joint (1/209, 0.5%) because the bone fragments were significantly displaced proximally by the gluteus medius. Multivariate analysis showed the combination of Type B femoral shape (in cases where the top of the great trochanter was inside the longitudinal central axis of the planned femoral stem in computed tomography (CT)- based three-dimensional templating) and a YAM of < 80% was the only risk factor for fracture. Conclusions: The preoperative greater trochanter BMD test (YAM < 80%) and three-dimensional femoral morphology (Type B femoral shape) provide useful information to mitigate the occurrence of perioperative greater trochanter fractures associated with THA using the anterolateral approach. [ABSTRACT FROM AUTHOR]

Introduction: A greater trochanteric fracture is a perioperative complication of primary total hip arthroplasty (THA) via an anterolateral approach. Although surgeons determine risk factors in the preoperative planning phase, no study explored the relationship between the planned femoral implant and greater trochanter. This study attempts to determine the risk factors for perioperative greater trochanteric fractures in primary THA via an anterolateral approach. Materials and methods: This retrospective single-institution study enrolled 440 patients (66 males and 374 females) who underwent primary THA via an anterolateral approach with a minimum follow-up of six months. First, we selected patients with perioperative greater trochanteric fractures, regardless of the need for additional surgery. Second, we investigated the risk factors for perioperative greater trochanteric fractures using the patients' demographic data, operative data, and femoral geometry data via univariate and multivariate analyses. Results: Perioperative greater trochanteric fractures occurred in 30 joints (30/440, 6.8%), and all cases were reported in women. Multivariate analysis revealed that in cases where the top of the great trochanter was inside the longitudinal central axis of the planned femoral stem in three-dimensional templating (Type B) was the only independent risk factor for perioperative greater trochanteric fracture (odds ratio, 14.6; 95% confidence interval, 5.88–36.1; P < 0.001). Conclusion: This study identified female sex and Type B femoral geometry as risk factors for perioperative greater trochanteric fracture via an anterolateral approach. Our results may reduce the incidence of perioperative greater trochanteric fractures associated with primary THA. [ABSTRACT FROM AUTHOR]

Total hip arthroplasty (THA) for patients with hip osteoarthritis improves hip flexion contracture, subsequently improving spinal sagittal balance. However, in some cases, spinal sagittal imbalance develops in the course after THA, and its risk factors remain unknown. We aimed to investigate the risk factors of progressive spinal sagittal imbalance after THA. This retrospective cohort study of a prospectively maintained database included female patients aged ≥50 years who underwent THA. Before performing THA, we obtained each patient's anthropometric and muscle strength measurements and whole-spine radiographs. Three years postoperatively, patients underwent whole-spine radiography to examine changes in the spinal sagittal balance. Patients were assigned into groups on the basis of their preoperative and 3 year postoperative sagittal vertical axis (SVA) values. Patients with 3 year postoperative SVA values ≥40 mm with an increase ≥30 mm were categorized into the imbalance group; the other patients were categorized into the non-imbalance group. Of 103 patients, 11 (10.7%) were in the imbalance group. In multiple logistic regression analysis, preoperative weak abdominal trunk muscle strength (ATMS) (p = 0.007) and small sacral slope (SS) (p = 0.005) were significant risk factors for progressive spinal sagittal imbalance. In conclusion, risk factors for progressive spinal sagittal imbalance after THA were weak preoperative ATMS and small SS. [ABSTRACT FROM AUTHOR]

Background: Postoperative gait speed, especially comfortable gait speed, is an important factor for predicting function after total hip arthroplasty (THA). In this study, we examined factors related to gait speed, including preoperative lower and upper-limb functional parameters and postoperative lower-limb alignment. In addition, we examined factors related to postoperative good comfortable gait speed (≥1.34 m/s: one indicator of a good clinical outcome). The purpose of this study was to determine if better preoperative functional parameters had a positive effect on postoperative gait speed.Methods: This prospective case-control study included 91 patients with hip osteoarthritis who underwent unilateral THA. Patients who had undergone a prior hip surgical procedure or had Crowe type-3 and 4 hips, complications after THA, knee osteoarthritis-related pain, and severe lumbar conditions were excluded. The 1-leg standing time (OLST) and knee extensor strength of the operatively treated side and the contralateral side and the functional reach test were examined preoperatively and at 1 year postoperatively. The leg-length discrepancy and global offset compared with the contralateral side and leg lengthening were examined using 3-dimensional models captured through computed tomographic scans.Results: The preoperative contralateral side OLST was a significant factor (p < 0.001) for postoperative comfortable gait speed, and the preoperative contralateral-side knee extensor strength was a significant factor (p = 0.018) for postoperative maximum gait speed. Leg-length discrepancy and differences in global offset after THA were not significant factors for postoperative gait speed. The preoperative comfortable gait speed with a cutoff value of 1.115 m/s (area under the receiver operating characteristic curve, 0.690 [95% confidence interval, 0.569 to 0.810]; p = 0.003; sensitivity of 65.5% and specificity of 74.2%) was an independent factor associated with a good postoperative comfortable gait speed. Preoperative contralateral-side OLST was a significant factor (p = 0.027) for preoperative comfortable gait speed.Conclusions: The preoperative contralateral-side, lower-limb functional status is a significant factor for postoperative gait speed. Early surgical intervention before the contralateral-side function declines or a preoperative rehabilitation intervention on the contralateral side may improve THA outcome.Level Of Evidence: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Introduction: This report is the first study to compare the clinical outcomes between cementless and cemented femoral prostheses in total hip arthroplasty (THA) with subtrochanteric femoral shortening osteotomy for Crowe type IV hips. Materials and methods: We identified 26 hips in 20 patients who had undergone cemented (n = 13) or cementless (n = 13) THA with subtrochanteric femoral shortening osteotomy for Crowe type IV hips with a minimum follow-up period of 2 years. The mean follow-up period was 60.8 ± 33.9 months (24–120 months). We compared radiological findings, postoperative clinical recoveries, postoperative complications, and implant survival rates. Results: In both groups, there were no cases of aseptic loosening for the acetabular and femoral implant. In terms of bone union at the osteotomy site, the mean duration was significantly longer in the cemented group (9.8 ± 4.2 months) than in the cementless group (5.0 ± 1.9 months). The clinical hip score in gait and pain at 3 months postoperatively was significantly higher in the cemented group than in the cementless group, while there were no significant changes at other timepoints between two groups. The number of postoperative complications was not significantly different between the two groups. The implant survival rate was 92% in the cementless group and 100% in the cemented group at 5 years postoperatively (P = 0.31). Conclusions: The cemented femoral prosthesis is superior to the cementless femoral prosthesis for early clinical recovery, while the duration required to achieve bone union at the osteotomy site is longer in the cemented femoral prostheses. It is possible for surgeons to perform successful hip reconstructions, regardless of the fixation method used for THA with shortening femoral osteotomy. [ABSTRACT FROM AUTHOR]

This study investigated the influence of the rotation of innominate bone on anterior pelvic plane (APP) tilt, the angle formed by the APP, and coronal plane of the body to determine whether the provision of proper information about the sagittal balance of the body by the value of the APP tilt (APPT). In total, 244 patients (171 females, 73 males) who were candidates for total hip or knee arthroplasty, periacetabular osteotomy, or shelf arthroplasty were included. The rotational angle of the innominate bone was quantified using computed tomography images at the level of the anterior superior, and anterior inferior iliac spine, and ischiopubic portion. Clustering analysis was performed to identify subtypes of innominate bone rotation. High, intermediate, and low internal rotational alignment groups were identified in females, characterized by rotational angles. Males were treated as one group, and no intergroup differences were observed in sacral slope (SS) and pelvic incidence. However, intergroup differences in APPT were found, indicating a variation in APPT irrespective of sagittal body balance. A negligible relationship between SS and APPT was observed in the high‐internal‐rotation group, intermediate‐internal‐rotation group, and male group, whereas a moderate correlation found in the low‐internal‐rotation group (r =.59). The results could suggest surgeons that the value of the APPT provides no information on the sagittal balance; therefore, it may be ignored for acetabular component positioning during preoperative planning for total hip arthroplasty. [ABSTRACT FROM AUTHOR]

Background: There is limited understanding of anterior acetabular component overhang, which induces groin pain, in post-periacetabular osteotomy (PAO) hips during conversion to total hip arthroplasty (THA). The aim of the study were to determine the following: (1) the differences in the amount of acetabular component overhang among pre-PAO hips and post-PAO hips in simulating THA; (2) the factors associated with the amount of component overhang in THA following PAO; (3) whether high component placement with elevation of the hip center by 10 mm reduces the amount of component overhang compared to the anatomical component position in THA following PAO. Methods: Computer-based simulations of acetabular component implantation were performed using preoperative and postoperative CT data from 30 patients undergoing PAO. Implantation was performed thrice in each patient: in pre-PAO hips (anatomical component position) and post-PAO hips (anatomical and high component position). Component overhang was measured on the axial plane, which passes through the component center. Results: Overhang was greater in post-PAO hips [mean (SD) overhang: 5.2 (2.9) mm, pre-PAO hips: 10.2 (4.6) mm, post-PAO hips-mean difference, 5.0 mm; p < 0.001]. A smaller distance between the pubic osteotomy and the acetabulum, and greater overhang in pre-PAO hips was independent factors associated with increased overhang in post-PAO hips. Overhang was smaller with the high component position than with the anatomical component position in post-PAO hips [mean (SD) overhang-3.5 mm (2.9) with high component position among post-PAO hips; mean difference, 6.6 mm; p < 0.001). Ten post-PAO hips with the anatomical component position had overhang of at least 12 mm (the likely threshold for groin pain). Of these, 9 hips had reduced overhang (< 12 mm) with the high component position. Conclusions: Acetabular component overhang was more severe in THA following PAO than in THA without prior PAO. Pubic osteotomy should be performed closer to the acetabular rim to prevent severe overhang in potential THA conversion cases. A high component position decreased the risk of severe overhang. [ABSTRACT FROM AUTHOR]

Purpose: A computed tomography (CT)-based hip navigation system is a useful tool for achieving precise implant alignment angle. However, it has the disadvantage of prolonged procedure duration. A prolonged procedure duration may increase the incidence of postoperative surgical site infection (SSI) or periprosthetic joint infection (PJI) following primary THA. Studies identifying whether CT-based hip navigation system increases the incidence of SSI and PJI compared to the free-hand technique for total hip arthroplasty (THA) are rare. The study aimed to assess whether the CT-based hip navigation system can cause SSI and PJI compared to the free-hand technique. Methods: We investigated 366 patients with osteoarthritis who completed the minimum 2-year follow-up and underwent primary THAs (n = 435), including 70 hips in 62 patients of the non-navigation group and 365 hips in 304 patients of the navigation group. We compared the incidence rate of SSI and PJI between the non-navigation group and navigation group. Results: Only three patients in the navigation group (0.8%) developed SSI or PJI, while no patient developed SSI or PJI in the non-navigation group. There was no significant difference in the incidence rate of SSI or PJI between the two groups (P = 1.0), although the mean operation time in the navigation group was about 20 min longer. Conclusions: CT-based hip navigation system may not be associated with SSI or PJI after primary THA, although it prolongs the operation time. [ABSTRACT FROM AUTHOR]

Background: A few previous studies have investigated patient satisfaction after total hip arthroplasty (THA) according to the degree of pelvic deformity. This study compared patient-reported outcomes after primary THA for Crowe types III, IV and I dysplasia.Methods: This retrospective, single-center, single-surgeon case-control study included patients who underwent primary THA between 2008 and 2016. We sent postal questionnaires to 38 patients with Crowe type III and IV dysplasia. Among the questionnaire respondents, 23 patients, excluding those with a follow-up period of < 1 year, were enrolled as the H group. The control group included 46 patients with Crowe type I, matched for sex, age, body mass index and surgical approach. To investigate the influence of femoral shortening osteotomy, the H group was divided according to whether femoral shortening osteotomy was performed. Ten patients underwent THA with femoral shortening osteotomy (FO group), while 12 patients underwent THA without femoral shortening osteotomy (N-FO group). Patient demographics, mean follow-up period, surgical information, pre- and postoperative leg length discrepancy (LLD), and perioperative complications were investigated. Clinical evaluations were performed using the Japanese Orthopaedic Association (JOA) scores, 36-item short-form survey (SF-36), net promotor score (NPS), visual analogue scale (VAS), and questionnaires. The VAS and SF-36 scores were determined only at final follow-up.Results: The H and control groups were not significantly different in the postoperative JOA scores and SF-36. In the H group, VAS at the final follow-up was significantly higher, and significantly more patients felt that postoperative rehabilitation was serious, expressing that they underwent THA for LLD correction. In addition, the VAS scores in the FO group was higher than those in the N-FO group. Postoperative LLD was significantly greater in the H group than in the control group. Each group had an NPS of > 50.Conclusion: The postoperative VAS score was higher in Crowe type III and IV dysplasia than in Crowe type I dysplasia, but no significant differences were detected in the postoperative satisfaction, JOA score, and SF-36 score. These findings may help explain the effects of THA preoperatively to patients with Crowe type III and IV dysplasia.Level Of Evidence: Therapeutic Level 3b. [ABSTRACT FROM AUTHOR]

Background: In total hip arthroplasty with computer navigation assistance, cup orientation is generally determined according to the coordinate system relative to the functional pelvic plane (FPP). However, there is a large difference in the cup anteversion between a posterior pelvic tilt relative to the computed tomography (CT) table in the sagittal plane and anterior pelvic tilt, even when the cup is set at the same orientation angle according to each FPP. The present study analysed this difference from the viewpoint of 3-dimensional (3D) coverage of the acetabular component (3D coverage) to determine how the 3D acetabular coverage is altered with changes in pelvic sagittal tilt. Methods: We analysed 3D-simulated acetabular coverage measured in 3D pelvic models reconstructed from the preoperative CT data of 50 patients. In each patient, we created 5 pelvic models with a sagittal tilt of 10° increments between 20° anterior tilt and 20° posterior tilt relative to the CT table. Results: We found that 3D coverage decreased as the pelvis tilted posteriorly. Particularly, there were significant differences between the pelvis with 20° anterior tilt and that with neutral tilt (p < 0.001). There was also a difference between the pelvis with neutral tilt and that with a 20° posterior tilt (p < 0.01). The mean decrease in 3D coverage between the pelvis with neutral tilt and that with 20° posterior tilt was 7.2 ± 1.6%. Conclusions: We found that 3D coverage differed among pelvis with different sagittal tilts when the cup orientation angle was determined according to FPP. [ABSTRACT FROM AUTHOR]

Purpose: Residual feeling of leg length discrepancy (LLD) is a common cause of patient dissatisfaction following total hip arthroplasty (THA). The purpose of this study is to propose a method for determining an optimal leg length correction goal in THA.Methods: We conducted a retrospective study of 132 patients to examine the radiographic LLD (R-LLD), perceived LLD (P-LLD), and whether or not the patient has an uncomfortable feeling about the leg length after THA.Results: The residual discomfort rate in all patients was 9.1% (12/132 patients), and ten of these 12 patients felt uncomfortable due to a longer leg length. When R-LLD was within 7 mm, the rate was 6.8% (8/118 patients), which is nearly equal to the rate of 7.8% (5/64 patients) in cases in which R-LLD was within 2 mm. On the other hand, when R-LLD was 8 mm or more, the rate was 57.1% (4/7 patients).Conclusions: The results of our study show that 7 mm may be a reasonable threshold for reducing the residual discomfort. However, even with little or no R-LLD, some patients will continue to experience discomfort. We think that this is because of pre-operative differences between R-LLD and P-LLD in such cases. If the patient has a pelvic declination on the affected hip side and a lumbar scoliosis angle that is convex toward the affected hip side before surgery, the ideal length may be a little shorter than the radiographic isometry, since such patients are likely to feel a longer leg length than that shown radiographically. [ABSTRACT FROM AUTHOR]

Purpose: To investigate whether anatomic and straight stems could reproduce the anteroposterior distance (AD) of the native femoral head and evaluate the effect of AD of the femoral head on range of motion (ROM) and bony impingement.Methods: This retrospective simulation study included 64 patients who had undergone primary total hip arthroplasty between 2012 and 2014. Using computed tomography (CT)-based templating software, anatomic and straight stems were inserted with same alignment. AD of the head centre was compared between the two stems and native anatomy. Furthermore, post-operative ROM was calculated, and correlation between AD and ROM was assessed.Results: There was a strong positive correlation between native anteversion (mean 21.9°) and anatomic stem anteversion (mean 22.5°) (R = 0.975, P < 0.001). There was no significant difference in AD between the native and anatomic stems (mean 37.7 and 38.8 mm, respectively), but AD of the straight stem was significantly lower than that of the native and anatomic stems. The straight stem showed a significantly lower ROM in flexion and internal rotation angles with 90° flexion (IR) than the anatomic stem (P < 0.05 and P < 0.001, respectively). AD showed a stronger correlation with ROM of IR than with stem anteversion.Conclusions: The anatomic stem could reproduce AD of the native femoral head centre, but the head centre of the straight stem in the same anteversion with anatomic stem translated significantly posterior, significantly decreasing the ROM of flexion and IR and increasing bony impingement of IR. To avoid bony impingement and acquire sufficient ROM, reproducing AD was important. [ABSTRACT FROM AUTHOR]

Purpose: There is no documented maximum amount that an extremity can be safely lengthened in primary total hip arthroplasty (THA) without neurologic or soft tissue complications. We retrospectively reviewed patients who underwent primary THA with acute limb lengthening and investigated the safety range for acute limb lengthening in primary THA.Methods: This study included 61 hips in 52 patients who underwent primary THA with acute limb lengthening (more than 2.5 cm) without femoral shortening osteotomy. The amount of lengthening was measured from pre-operative and post-operative X-ray films using computer graphics software, then the ratios of the amount of lengthening to femoral length (L/F ratio = amount of lengthening / femoral shaft length × 100) were calculated. We investigated correlation with nerve and soft tissue complications at operation in regard to this index.Results: The average amount of lengthening was 3.0 cm (2.5 to 4.8). The average L/F ratio was 7.9 (6.2 to 12.9). There were seven nerve complications and two soft tissue complications in the whole series. In all nine complications, eight indicated higher L/F ratios than 8.7. Altogether, 12 hips indicated a higher L/F ratio than 8.7; 66% of them showed neurological or soft tissue problems. ROC curve analysis indicated that the optimal cutoff value of the L/F ratio was 8.7, which predicted acute lengthening-related complications with a sensitivity of 88.9% and a specificity of 92.3% (AUC = 0.88).Conclusion: The patients who underwent THA with acute lengthening of more than 8.7% of femoral shaft length are at high risk of complications caused by acute limb lengthening in primary THA. [ABSTRACT FROM AUTHOR]

Background: In THA, using a larger femoral head can increase the oscillation angle and jumping distance. However, there have been no reports which indicate precisely how increasing the jumping distance leads to an increase in the angle from impingement to dislocation (jumping angle). In this study, we clarified the jumping angle of various head diameters and its relationship with pelvic morphology.Methods: Using a three-dimensional templating system, virtual THA and ROM simulations were performed in 82 patients. We investigated the distance between bony and prosthetic impingement points and the head centre and calculated the jumping angle for various head diameters. We measured various pelvic shapes and length to clarify the relationship between pelvic morphology and impingement distance.Results: Jumping angles were 7.7° ± 3.2°, 12.1° ± 1.6°, 15.4° ± 2.5° and 10.0° ± 3.0° with flexion, internal rotation with 90° flexion (IR), extension and external rotation (ER), respectively, when we used a 22-mm head diameter. Bony jumping angle increased about 0.5°, 0.8°, 1.0° and 0.7° per 2-mm increase in head diameter with flexion, IR, extension and ER. On the other hand, prosthetic jumping angle remained almost stable at about 31°. Impingement distance was related to pelvic morphology in all directions. Bony jumping angles differed with ROM; the biggest was seen with extension, followed by IR, ER and flexion. On the other hand, bony jumping angle was less than prosthetic jumping angle in all cases.Conclusion: Bony jumping angles differed with ROM; the biggest was seen with extension, followed by IR, ER and flexion. Prosthetic impingement angles were stable. In addition, the bony jumping angle was less than the prosthetic jumping angle in all cases. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to conduct a prospective clinical trial to investigate the accuracy of an MRI-based patient-specific acetabular instrument guide during THA.Methods: We conducted a prospective consecutive review of 14 hips in 14 patients who underwent primary THA with a posterolateral approach between September 2016 and February 2018. All preoperative planning and postoperative evaluations were completed on CT-based templating software. A pelvic MRI was taken to create a patient-specific surgical instrument guide. In order to assess the effect of increased experience on accuracy, we divided the cases into two groups according to when surgery was performed and investigated the absolute error in the acetabular component angle between preoperative planning and the postoperative state for each of the groups.Results: We did not experience postoperative complications such as implant early dislocation in any of the cases. The absolute errors of acetabular implant angle using the patient-specific instrument guide were 3.7° ± 2.2° inclination and 4.5° ± 3.9° anteversion. The absolute error of the initial group was 4.7° ± 2.1° inclination and 6.1° ± 4.0° anteversion; for the later group, it was 2.8° ± 1.8° inclination and 3.2° ± 2.9° anteversion. There was a significant difference in the absolute error of acetabular implant placement between the initial group and the later group.Conclusions: We believe this study shows that MRI-based patient-specific instrumentation may be a useful alternative to surgical tracking during THA once the slight learning curve has been overcome. [ABSTRACT FROM AUTHOR]

Introduction: The influence of stem sagittal alignment on clinical outcomes is unclear in total hip arthroplasty (THA). The purpose of this study is to assess the relationship between stem sagittal alignment and clinical and radiographic outcomes using 3D-CT.Materials and methods: We performed 370 consecutive primary THAs between 2009 and 2013. After exclusion, 102 hips in 89 patients using single tapered-wedge stem were included. Mean follow-up was 4.7 years. Stem sagittal alignment was measured using CT, and patients were divided into flexion and neutral alignment groups. Clinical and radiographic outcomes were compared between two groups. Furthermore, we evaluated the anterior femoral offset and initial contact state.Results: There were no significant differences in clinical or radiographic outcomes between two groups. CT data analysis and multiple regression analysis showed flexion alignment increased anterior femoral offset (AFO) and Gruen zone 4 contact area.Conclusions: There was no significant difference in clinical or radiographic outcomes between flexion and neutral alignment of the tapered-wedge stem at an average of 4.7 years of follow-up. The increase of AFO and distal contact area in flexion alignment could affect the improvement of impingement-free range of flexion and intraoperative fracture. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the various impingement angles (including both bony and prosthetic impingement) and impingement types that can occur after THA, even when the same combined anteversion parameter is used. We also investigated the relationship between impingement angle and acetabular morphology or femoral anteversion.Methods: We evaluated 83 patients with no hip arthritis. We divided them into six groups according to acetabular CE angle (≤15°, >15-≤25°, and >25°) and femoral anteversion (≤20° and >20°). Using three-dimensional templating software, we changed stem and cup anteversion to satisfy a combined anteversion (CA) of 50° in each hip (stem anteversion + cup anteversion = 50°) and investigated the resulting impingement angles.Results: Even with the same CA, differences in impingement angle occurred: 18.3° ± 7.2° with flexion, 30.2° ± 9.7° with internal rotation at 90° flexion, 20.2° ± 12.5° with extension, and 26.2° ± 7.8° with external rotation. As stem anteversion increased, the impingement type changed from prosthetic impingement to bony impingement in flexion and internal rotation and from bony impingement to prosthetic impingement in extension and external rotation. The flexion angle and internal rotation angle at 90° flexion increased (p < 0.016) as CE angle decreased. There were no significant differences between high and low femoral anteversion.Conclusions: Combined anteversion theory should be used with care because of large differences in impingement angles. A stem anteversion of 30° and cup anteversion of 20° appear to be ideal for obtaining a larger impingement angle under this condition. [ABSTRACT FROM AUTHOR]

Traditionally, Charcot arthropathy has been considered an absolute contraindication for total hip arthroplasty (THA). However, some recent reports have shown that good short- to mid-term results can be achieved by improving the durability of the implant. This paper reports the mid- to long-term results of THA in two patients with Charcot hip joints caused by congenital insensivity to pain with anhydrosis. Both patients suffered multiple posterior dislocations in the six months immediately following surgery. However, with the continuous use of a hard abduction brace, one patient was eventually able to walk with a lofstrand cane and the other with the use of one crutch. Although one patient experienced a dislocation five years after surgery, X-rays taken after nine years and five years, respectively, revealed no clinical signs of implant loosening. We conclude that, with careful planning and appropriate precautions, THA may be a viable treatment option for Charcot hip joints caused by congenital insensivity to pain with anhydrosis. [ABSTRACT FROM AUTHOR]

Background: Past reports have shown the tendency of posterior pelvic tilt to increase over time after total hip arthroplasty (THA). We have hypothesized that the volume and extent of released joint capsule may influence the change in postoperative pelvic tilt. This study was conducted to ascertain whether surgical approach during THA (posterior or anterior) has an effect on postoperative changes in pelvic tilt. Methods: We conducted a retrospective review of 81 hips in 60 patients. Patients classified as Crowe group 2, 3, and 4, those who had multiple previous compression fractures, and those with spinal fusion due to spinal arthrosis were excluded. Also, those who had previously undergone THA or total hip resurfacing also were excluded. Patients were divided into two groups, those with preoperative anterior pelvic tilt and those with posterior tilt. Preoperative and postoperative X-rays and CT scans for each group were assessed to determine the chronological change in pelvic tilt, and the data were statistically analyzed for patients who had experienced both the posterior and anterior approaches. Results: Regardless of surgical approach, there was no significant difference in the mean change in postoperative APP angle over time in either the bilateral or unilateral cases or in the groups of preoperative anterior or posterior pelvic tilt. Conclusions: Our results showed that surgical approach does not influence postoperative pelvic tilt after THA. In preoperative planning for THA, therefore, surgeons may need not to consider the difference of surgical approach with regard to postoperative changes in pelvic tilt. [ABSTRACT FROM AUTHOR]

Background: Periprosthetic fractures of the acetabulum occurring during primary THA are rare. Periprosthetic occult fractures are defined as those not identified by the surgeon during the procedure which might be missed on a routine postoperative radiograph. However, it is unclear how frequently these fractures occur and whether their presence affects functional recovery.Questions/purposes: In this study, using routine CT scans that were obtained as part of another primary hip arthroplasty study protocol, we retrospectively assessed (1) the prevalence of occult fractures of the acetabulum occurring during primary THA, (2) the location of occult fractures of the acetabulum during THA, and (3) risk factors contributing to such occult fractures.Methods: Between 2004 and 2013, our institute performed 585 primary THAs (cementless or hybrid) in 494 patients with DICOM pre- and postoperative CT; during the period in question, all patients undergoing THA underwent CT before and after surgery. Preoperative CT images were taken as part of a CT-based three-dimensional templating software and navigation system. Postoperative CT images were taken an average of 1 week after surgery as part of a different protocol to evaluate cup position, restoration of leg length and offset, volume of postoperative hematoma to assess anticoagulation effects after THA, and fractures that were not found on routine postoperative radiographs (which we defined as occult fractures). Patients with a history of prior pelvic osteotomy, trauma, and infection were excluded (88 patients/99 hips); 406 patients (102 males and 304 females; 486 hips) form the basis of this report. The mean age of the patients was 60 ± 11 years, with a mean BMI of 23 ± 4 kg/m2. The mean followup of the patients with periprosthetic fracture of the acetabulum was 58 ± 28 months (range, 12-131 months). Potential risk factors for occult acetabular fracture including age, sex, BMI, preoperative diagnosis, additional dome screw fixation, composition and size of each cup, and acetabular design were examined in multivariate analysis. Acetabular component designs were categorized as true hemispheric, peripheral self-locking, and elliptical; during the period in question the indications for each cup design were based on the brand of stem used. Comparison between preoperative and postoperative CT images was done to detect the fractures. Patients with fractures identified during surgery were treated with additional dome screw fixation and a 3-week period of nonweightbearing. Patients with occult fractures in this series did not receive additional treatment as we had confirmed secure fixation of the cup during surgery.Results: Occult fractures occurred in 41 hips (8.4%); periprosthetic fractures of the acetabulum were seen during surgery in an additional two hips (0.4%). The superolateral wall was the most frequent location for occult fractures of the acetabulum. After controlling for relevant confounding variables, only the use of peripheral self-locking cups was associated with an increased risk of occult fracture (odds ratio [OR], 2.6 compared with hemispheric cups; 95% CI, 1.2-5.6; p < 0.05). All patients with occult fractures showed bone ingrowth fixation at the final followup, without any additional surgical intervention.Conclusions: Periprosthetic occult fractures of the acetabulum may occur relatively frequently during press-fit impaction. We observed a higher rate of fractures associated with the use of peripheral self-locking components. Occult acetabular fractures not detected on routine postoperative plain films may be ignored if secure fixation of the cup has been confirmed during the operation.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: The linea aspera is the rough, longitudinal crest on the posterior surface of the femoral shaft. Most orthopedic surgeons depend on the linea aspera as an intraoperative landmark identifying the true posterior aspect of the femur. We investigated the position of the linea aspera to verify whether the surgeon can rely on this accepted belief.Material and Method: One hundred and thirty-three femora from 73 patients were evaluated. Four CT cuts were done of the mid femur, and we measured the angle of rotation of the linea aspera at each cut.Results: The linea aspera was externally rotated in most femora evaluated; average angles of rotation were 15.4°, 14°, 11.7°, and 11.5° at 10, 15, 20, and 25 cm from the intercondylar line, respectively. The angle of rotation of the linea aspera was positively correlated with femoral neck anteversion angle and negatively with age.Conclusion: The linea aspera is exactly posterior in a minority of individuals, while it is externally rotated to varying degrees in the majority of individuals. The degree of rotation was positively correlated with femoral neck anteversion angle, and negatively with age. To avoid implant malrotation, accurate estimation of the rotation angle should be determined preoperatively.Level Of Evidence: Level IV. [ABSTRACT FROM AUTHOR]

Background: It would be ideal if surgeons could precisely confirm whether the planned femoral component achieves the best fit and fill of implant and femur. However, the cortico-cancellous interfaces can be difficult to standardize using plain radiography, and therefore, determining the contact state is a subjective decision by the examiner. Few reports have described the use of CT-based three-dimensional templating software to quantify the contact state of stem and femur in detail. The purpose of this study was to use three-dimensional templating software to quantify the implant-femur contact state and develop a technique to analyze the initial fixation pattern of a cementless femoral stem. Methods: We conducted a retrospective review of 55 hips in 53 patients using a short proximal fit-and-fill anatomical stem (APS Natural-Hip™ System). All femurs were examined by density mapping which can visualize and digitize the contact state. We evaluated the contact state of implant and femur by using density mapping. Results: The varus group (cases that had changed varus 2° by 3 months after surgery) consisted of 11 hips. The varus group showed no significant difference with regard to cortical contact in the proximal medial portion (Gruen 7), but the contact area in the distal portion (Gruen 3 and Gruen 5) was significantly lower than that of non-varus group. Density mapping showed that the stem only has to be press-fit to the medial calcar, but also must fill the distal portion of the implant in order to achieve the ideal contact state. Conclusions: Our results indicated that quantifying the contact state of implant and femur by using density mapping is a useful technique to accurately analyze the fixation pattern of a cementless femoral stem. [ABSTRACT FROM AUTHOR]

Introduction: Poor long-term results of total hip arthroplasty (THA) can result from femoral component misalignment. There are few reports that discuss the effectiveness of intraoperative radiographs for placing femoral components. This study is a retrospective review to find out the usefulness of intraoperative radiographs in detecting and improving the femoral component misalignment in posterior-approached primary THA. Materials and methods: The study group included 150 primary THAs performed between September 2009 and April 2012. After the trial component insertion in lateral decubitus position, intraoperative radiography was performed. The surgeon assessed the femoral component position in three aspects: alignment, leg length, and offset. If it is not following the preoperative template, the surgeon makes the intraoperative adjustments to change the femoral component position. After the operation, postoperative radiograph was taken; the same parameters were measured and were compared to intraoperative findings. The changes in each parameter were classified into three categories: satisfactory, no change, and unsatisfactory. Among the three parameters, if one is satisfactory and the others are not unsatisfactory, we defined it as accurate positioning of the femoral component. Results: Intraoperative adjustments were made in 122 cases (81.3 %). The adjustments included changes in the component size (35.3 %), component alignment (38.6 %), femoral offset (14.0 %), and additional femoral neck cuts (56.0 %). As a result, accurate positioning was successfully achieved in 112 cases (91.8 %) by taking intraoperative radiographs. Conclusion: Our data suggest that intraoperative radiography is a useful method for detecting the errors of placing the femoral components, and the success of a surgeon to correct those errors after detecting them intraoperatively. [ABSTRACT FROM AUTHOR]

Purpose: This study investigates the accuracy of a computed tomography (CT)-based navigation system for accurate acetabular component placement during revision total hip arthroplasty (THA). Methods: We performed a retrospective review of 30 hips in 26 patients who underwent cementless revision THA using a CT-based navigation system; the control group consisted of 25 hips in 25 patients who underwent cementless primary THA using the same system. We analysed the deviation of anteversion and inclination angles among the pre-operative plan, intra-operative records from the navigation system and data from postoperative CT scans. Results: There were no significant differences between groups ( P < 0.05) in terms of mean deviation between pre-operative planning and postoperative measurements or between intraoperative records and postoperative measurements. Conclusion: CT-based navigation in revision THA is a useful tool that enables the surgeon to implant the acetabular component at the precise angle determined in pre-operative planning. [ABSTRACT FROM AUTHOR]

It is well known that the coagulation factor XIII (FXIII) is deeply involved in wound healing and tissue regeneration. We measured the plasma levels of FXIII (FXIII levels) before and after surgery in 80 patients with bone tumors [benign tumors in 30 patients (BT group), malignant tumors in 30 patients (MT group), and carcinoma metastasis in 20 patients (CM group)] and in the control group which consisted of 30 patients with osteoarthritis of the hip joint who had underwent total hip arthroplasty (THA). The numbers of patients whose preoperative FXIII level was below the lower limit of normal were as follows: 0 (0%) among 30 patients in the control group; 7 (23%) among 30 patients in the BT group; 12 (40%) among 30 patients in the MT group; and 9 (45%) among 20 patients in the CM group. Among patients with bone tumors examined in this study, patients with osteosarcoma who underwent chemotherapy showed a significant decrease in FXIII levels (p < 0.01). We indicated not only FXIII levels in patients with bone tumors, but also the natural time-course of FXIII levels in patients who underwent orthpaedic surgery of THA at the first time. [ABSTRACT FROM AUTHOR]

Sports activity has many benefits in cancer survivors. A key one is having sport activity contribute to the well-being of the individual. However, there are no guidelines about the intensity and kind of postoperative mobility workouts after hip or knee megaprosthetic treatment. Opinion research about sports after modular bone and joint replacement may provide an understanding of surgeons' attitudes on sports activity after megaprostheses of the hip and knee joint. A web survey with members of three international professional organizations of orthopedic tumor reconstructive surgeons was conducted between September 2016 and January 2018. Members were invited via personalized emails by the European Musculoskeletal Oncology Society (EMSOS), the International Society of Limb Salvage (ISOLS), and the Musculoskeletal Tumor Society (MSTS). The questionnaire included 26 questions. A total of 149 surgeons started the survey, and 76 finished the entire survey (American Association for Public Opinion Research (AAPOR) second response rate (RR2) EMSOS: 12.3%; ISOLS: 21.9%; MSTS: n/a). More than half of the respondents encourage sarcoma survivors after megaprosthetic treatment to reach an activity level that would allow them to regularly participate in active sporting events of University of California, Los Angeles (UCLA) activity level 7 and higher. Orthopedic tumor reconstructive surgeons do fear a number of complications (periprosthetic fracture, allograft failure/fracture, loosening, prosthetic or bearing failure, and early polyethylene wear) due to sports activity after modular bone–joint replacement, but they actually witness fewer complications than they conceptually anticipated. According to the surgeons' opinions, between four to seven types of sports after surgery could reasonably be recommended depending on the type of hip or knee procedures. This survey provides insights into opinions on what could be recommended, what could be allowed if surgeons and their patients agree on the potential negative outcome, and which sports should definitely not be allowed after hip and knee megaprostheses. [ABSTRACT FROM AUTHOR]

Background: Locomotive syndrome (LS) is a predictive factor of future motor dysfunction. Our aim was to evaluate the change in the total LS grade and, its the association with the Japanese Orthopaedic Association (JOA) hip score after total hip arthroplasty (THA) among patients with hip osteoarthritis.Methods: This was a prospective case-control study of 72 patients who underwent primary THA. The functional outcomes were measured before, and at 6 and 12 months after THA. LS was evaluated using the following tests: stand-up test, 2-step test, and 25-question Geriatric Locomotive Function Scale (GLFS-25). In addition, factors affecting the improvement of LS grade were examined.Results: Prior to THA, 7% and 93% of patients were classified as LS grades 1 and 2. At 6 months after THA, an improvement in the total LS grade was observed in 57% of patients, with this percentage further increasing to 65% at 1 year. Only the preoperative GLFS-25 was correlated with the preoperative JOA hip scores. The postoperative GLFS-25 and the two-step test were correlated with the postoperative JOA hip scores. The preoperative functional reach test (FRT) was significantly correlated with the total LS grade improvement.Conclusions: THA can improve the total LS grade in 65% of patients at 1 year postoperatively. Improvement was largely achieved in the first 6 months after THA, with a change from LS grade 2 to grade 1. FRT could be used an indicator of the total LS grade improvement. [ABSTRACT FROM AUTHOR]

Background: There have been no studies on the differences in impingement-free angle that result from different combined anteversion (CA) patterns. The aim of this study was to find the optimal CA pattern for achieving a favorable impingement-free angle, including bony and prosthetic impingement, in total hip arthroplasty.Methods: We evaluated 100 patients with no hip arthritis. We investigated the impingement-free angle (flexion, internal rotation with 90° flexion, extension, and external rotation) after changing the stem and cup anteversions to satisfy several CA patterns [cup anteversion + stem anteversion = 30°, 40°, 50°, and 60°; cup anteversion + 0.7 × stem anteversion = 37.3° (:Widmer's theory); and cup anteversion + 0.77 × stem anteversion = 43.3° (:Yoshimine's theory)] using 3-dimensional templating software.Results: The impingement-free angle changed dramatically among the various CA patterns. The optimal CA was changed by various stem anteversion. Only CA: Widmer with stem anteversion of 20° satisfied daily-life range of motion (ROM) requirements (flexion ≥130°, internal rotation with 90° flexion ≥ 45°, extension ≥ 40°, external rotation ≥ 40°).Conclusion: Good impingement-free angle cannot be obtained with single fixed CA. Different CA patterns should be used, depending on the differences in the stem anteversion. A CA of 30° with 0° ≤ stem anteversion ≤10°; a CA:Widmer with 20° of stem anteversion; a CA of 40° or Widmer with 30° of stem anteversion. When stem anteversion is ≥40°, CA should be decided by each patient's state. Among them, a stem anteversion of 20° with cup anteversion of 23.3° was found to be the best CA pattern. [ABSTRACT FROM AUTHOR]

Background: One of the serious postoperative complications associated with joint replacement is bacterial infection. In our recent investigations, iodine supported titanium implants demonstrated antibacterial activity in both in vitro and in vivo studies. The surfaces of the implants have porous anodic oxide layer with the antiseptic properties of iodine. According to the literature the titanium with porous anodic oxide have good osteoconductivity. But it is not clear whether the properties of iodine influence bone bonding of implants.Objectives: The aim of this study is to evaluate the influence of the properties of iodine and porous anodic oxide layer in the bone bonding ability of titanium implants.Study Design& Methods: Titanium rods were implanted in intramedullary rabbit femur models, in regard to the cementless hip stem. The implant rods were 5 mm in diameter and 25 mm in length. Three types of titanium rods were implanted.One was untreated titanium (control group (CL)), another was titanium with oxide layer without iodine (oxide layer group (OL)), and the other was Iodine treated Titanium (iodine group (ID)). The rods were inserted into the distal femur. We assessed the bonding strength by a measuring pull-out test at 4, 8, and 12 weeks after implantation. The bone-implant interfaces were evaluated at 4 weeks after implantation.Results: Pull-out test results of the ID implants were 202, 355, and 344 N, and those of the OL implants were 220, 310, 329 N at 4, 8, and 12 weeks, significantly higher than those of the CL implants (102, 216, and 227 N). But there were no significant difference in ID implants and OL implants. Histological examination revealed that new bone formed on the surface of each types of implants, but significantly more bone made direct contact with the surfaces of the ID implants and OL implants.Conclusions: This research showed that new type of coating, iodine coated titanium has low toxicity and good osteoconductivity. [ABSTRACT FROM AUTHOR]

Introduction: Preoperative planning with computed tomography (CT)-based three-dimensional templating has been expanded to achieve more precise placement of hip components. However, few reports have addressed the utility of three-dimensional surgical planning software for secondary osteoarthritis cases. This study therefore investigated the value of CT-based three-dimensional templating software for preoperative planning in primary total hip arthroplasty (THA), with an emphasis on developmental dysplasia of the hip. Materials and methods: We performed a retrospective review of 65 hips in 57 patients who underwent cementless primary THA. The preoperative diagnosis was secondary osteoarthritis in all cases due to developmental dysplasia of the hip. All preoperative planning and postoperative evaluations were completed using CT-based three-dimensional templating software. We analyzed the accuracy of stem size prediction and cup size prediction, the reproducibility of preoperative and postoperative stem anteversion, and the absolute error in preoperative and postoperative stem anteversion using CT-based three-dimensional templating software. Results: The sizes of 65 % of the femoral stems (42/65) were estimated exactly, and 98 % (63/65) were accurately estimated to within one stem size. The final acetabular cup sizes corresponded exactly to the preoperatively planned size in 92 % of all cases (62/65). 100 % of the cup size estimates were accurate to within one cup size. There was strong reproducibility of preoperative and postoperative stem anteversion ( r = 0.88, P < 0.05). The absolute error in stem anteversion was 4.0° ± 3.6°. Conclusions: Using CT-based three-dimensional templating software made it possible to achieve reproducible stem anteversion and choose accurate stem and cup sizes in patients with developmental dysplasia of the hip. [ABSTRACT FROM AUTHOR]