The Long-Term Efficacy of Computed Tomography-Navigated Total Hip Arthroplasty: An 18-Year Follow-Up Study

Backgroumd: There have been few reports on the long-term survival of computed tomography (CT)-navigated total hip arthroplasty (THA), which should lead to a lower incidence of dislocation and loosening. In this study, we examined survivorship, dislocation, and loosening incidence using plain radiographs over a minimum 15-year follow-up after CT-navigated THA.

METHODS

We retrospectively reviewed 145 consecutive CT-navigated THAs for >15 years. We surveyed the angles placed in both the acetabular and femoral components, survivorship, the occurrence of dislocation, the revision rate, and the fixation grade of the acetabular component.

RESULTS

The mean follow-up duration was 18.4 years. Overall, 73.8% of THAs were within the safe zone of Lewinnek. There were four dislocations (2.8%), with three occurring within 1 month after surgery and the other within 7 years after surgery. Revision THA was performed in one case (0.69%); consequently, the survival rate was 99.3%. The fixation grade was evaluated in 144 hips, and those were evaluated as having "no loosening".

CONCLUSIONS

CT-navigated THA was speculated to contribute to long-term survivorship, with a low rate of loosening, even after 18 years of follow-up. It was speculated that the acetabular component was placed at an acceptable insertion angle and a suitable position for stable initial fixation.

Associations of Lower-Limb Phase Angle with Locomotion and Motor Function in Japanese Community-Dwelling Older Adults

Whole-body phase angle (PhA) is associated with motor function and geriatric diseases. However, it was unclear which parts of the upper- or lower-limb PhA were involved. This study investigated the differences in the PhA of the upper and lower extremities and their relationships with frailty, locomotive syndrome indices, and motor function in community-dwelling older adult participants. This study was a cross-sectional observational study. In 69 community-dwelling older adults, the PhA at each measurement site (whole body, upper limbs, and lower limbs), motor function, Kihon Checklist (KCL), and 25-Geriatric Locomotive Function Scale (GLFS-25) were measured. This study examined differences in each PhA and its relationship with motor function and geriatric diseases. Multiple regression analysis was performed using GLFS-25 as the dependent variable and sex and lower-limb PhA as independent variables. In this cohort (mean age: 72.3 ± 5.7 years; 18 males and 51 females), lower-limb PhA was significantly lower than upper-limb PhA. Unlike other PhAs, lower-limb PhA was related to grip strength, TUG, F/w, and GLFS-25. Multiple regression analysis showed that the lower-limb PhA was independently related to GLFS-25. Cellular health of the lower extremity is associated with gait, standing function, and indicators of locomotive syndrome.

Relationship between the Hip Abductor Muscles and Abduction Strength in Patients with Hip Osteoarthritis

This study aimed to determine which muscle the gluteus maximus, gluteus medius, gluteus minimus (Gmin), or tensor fasciae latae (TFL) contributes most to hip abduction strength and to identify effective sites for cross-sectional area (CSA) Gmin and TFL measurement in hip osteoarthritis (OAhip) patients. Twenty-eight patients with OAhip were included. The muscle CSA and volume were determined using magnetic resonance imaging. Peak isometric strength was determined using hand-held dynamometry. Muscle volumes were normalized to the total muscle volume of hip abductors. Multiple regression analysis was performed. The difference between the CSA of Gmin and TFL was calculated, and correlations with volume and muscle strength were determined. Gmin volume was related to abductor muscle strength (p=0.042). The peak CSA of the Gmin correlated with muscle volume and strength. The CSA of the TFL correlated with volume, with no difference between the CSA of the most protruding part of the lesser trochanter and peak CSA. Gmin volume was strongly related to abductor muscle strength. Peak CSA is a useful parameter for assessing the CSA of the Gmin among patients with OAhip. The CSA of the TFL should be measured at the most protruding part of the lesser trochanter.

Analysis of Phase Angle and Balance and Gait Functions in Pre-Frail Individuals: A Cross-Sectional Observational Study

We measured the muscle mass and phase angle of each body part to evaluate the relationship between balance and gait functions in individuals with a pre-frailty status. This cross-sectional observational study determined the skeletal muscle mass-to-body weight ratio and phase angles of 21 control (robust) and 29 pre-frail subjects. Their Brief-Balance Evaluation Systems Test, Timed Up-and-Go (TUG) test, Life-Space Assessment, and Modified Fall Efficacy Scale scores plus the relationship between muscle mass, phase angle, and motor function were evaluated. In the pre-frailty group (three males, 26 females, aged 75.58±7.60 years), significant correlations were noted between the Brief-Balance Evaluation Systems Test score and lower-limb (r=0.614) and wholebody (r=0.557) phase angles, and between the TUG test score and lower-limb muscle mass-to-body weight ratio (r=-0.616), lower-limb phase angle (r=-0.616), and whole-body phase angle (r=-0.527). Evaluating the phase angle of the lower extremities of pre-frail patients and intervening accordingly may help clinicians maintain and improve these patients' balance and gait functions.

Three-dimensional Evaluation of Abnormal Gait in Patients with Hip Osteoarthritis

Indexes for objectively evaluating abnormal gait in hip osteoarthritis (OA) patients and determining effective interventions are unclear. We analyzed the abnormal gait of hip OA patients by focusing on movements of the trunk and pelvis to establish an effective evaluation index for each direction of motion. We studied 28 patients with secondary hip OA due to developmental dysplasia of the hip and 16 controls. The trunk and pelvic movements during gait were measured in the medial-lateral (x), vertical (y), and back-and-forth (z) directions by a triaxial angular accelerometer. Gait speed, steps, step length, muscle strength, range of motion, and timed up-and-go (TUG) test performance were measured. We determined the correlations between physical function and the index of abnormal gait in the hip OA patients. Movements other than trunk and pelvic motions in the y-direction indicated abnormal gait in the patients. Significant correlations were found between abnormal gait and range of motions (extension, internal rotation), TUG score, stride length, and steps. The TUG test, stride length and steps were important for evaluating abnormal gait in hip OA patients. Individual interventions for each movement direction are required.

Appropriate sites for the measurement of the cross-sectional area of the gluteus maximus and the gluteus medius muscles in patients with hip osteoarthritis

PURPOSE

To evaluate the relationship between the volume, cross-sectional area, and peak isometric muscle strength of the gluteus maximus and gluteus medius muscles in patients with hip osteoarthritis, and to use this information to identify effective sites for measurement of the cross-sectional area of these muscles.

METHODS

Twenty-four patients with hip osteoarthritis were included. The muscle cross-sectional area and volume were calculated from magnetic resonance images. The cross-sectional area was calculated at three levels: the inferior point of the sacroiliac joint, just above the femoral head, and at the greatest muscle diameter. Peak isometric strength was assessed using hand-held dynamometry, using the extension and external rotation for the gluteus maximus and abduction and internal rotation for the gluteus medius. Measured outcomes were compared between the two muscles, and the association between muscle volume, cross-sectional area, and peak isometric muscle strength was evaluated using Pearson's correlation.

RESULTS

Volume was correlated with the cross-sectional area in the gluteus maximus (r ≥ 0.707) and with the cross-sectional area (r ≥ 0.637) and peak isometric strength (r ≥ 0.477) in the gluteus medius. There was no difference between the cross-sectional area measured at the greatest muscle diameter and just above the femoral head (p = 0.503) for the gluteus maximus and at the inferior point of the sacroiliac joint (p = 0.651) for the gluteus medius.

CONCLUSION

The cross-sectional area, when used to calculate the muscle volume, should be evaluated just above the femoral head for the gluteus maximus and at the inferior point of the sacroiliac joint for the gluteus medius.

Stature estimation formulae based on bony pelvic dimensions and femoral length

We investigated the feasibility of estimating living stature in Japanese subjects using femoral length and pelvic dimensions measured on three-dimensional (3D) pelvic models reconstructed from cross-sectional computed tomography (CT) images. For this cross-sectional study, we recruited 106 healthy Japanese subjects. Maximum and bicondylar femoral length, as well as pelvic width, depth, and height, were measured on 3D bone models reconstructed from multi-slice CT images. The correlation of stature with each parameter was evaluated, and multiple regression equations were derived as formulae for living stature estimation. Prediction accuracy was evaluated as the mean absolute difference (MAD) between the measured and estimated statures. Maximum and bicondylar femoral lengths were similar and showed strong correlations with stature (> 0.8 in both males and females). Among the pelvic dimensions, height (craniocaudal length) showed the strongest correlation with stature in both males (r = 0.649) and females (r = 0.684). Formulae using femoral length plus pelvic height provided the best estimation of living stature in both males and females (MAD, 25-26 mm). Among the studied pelvic dimensions, height provided the best estimation of living stature when used alone (MAD, 34-36 mm) in both males and females. The intraclass correlation coefficients were high (> 0.9) for both intraobserver and interobserver reliability. Femoral length and pelvic height measured on CT images are reliable predictors of living stature in the Japanese population. Such tools are particularly useful in disaster victim identification, when the long bones are often not intact but the pelvic bones are.

Atypical femoral fracture associated with delayed union for which the cessation of alendronate and daily administration of teriparatide contributed to fracture healing: histopathological evidence of the enhancement in bone formation parameters

A female patient with systemic lupus erythematosus developed an atypical femoral fracture of the left femur after 5 years of glucocorticoid and alendronate therapy. We performed intramedullary nailing. However, 1 week later, we performed a revision surgery using a locking plate and an iliac bone graft because of displacement at the fracture site. At this stage, alendronate was discontinued and daily teriparatide was introduced and continued for 24 months. Twenty months after the revision surgery, a re-revision surgery was performed with an iliac bone graft because of breakage of the locking plate and fracture non-union. Fracture healing was eventually obtained 15 months after the re-revision surgery. Biopsies of the ilium before the treatment and 20 months after daily teriparatide treatment were evaluated. The histology revealed that proliferating osteoid and cuboidal osteoblasts were detected around the osteoid tissue after teriparatide treatment. Bone histomorphometry findings showed that bone volume parameters and osteoid parameters prominently increased with the teriparatide treatment, but not bone resorption parameters. Laboratory findings revealed the elevation of bone-specific alkaline phosphatase (24 U/L at 7 months) compared to its pre-teriparatide level (8.1 U/L) and increased bone mineral density of the hip (from -0.2 to 0.0 in T-score). These data indicated that the discontinuation of alendronate and initiation of teriparatide treatment activated bone-forming ability in our patient and may have contributed to fracture healing.

Tibiofemoral rotation is related to differences in the lateral femoral condyle configuration in both normal subjects and women with hip dysplasia: a three-dimensional analysis

Background

We assessed the morphological differences in the knee joint related to knee rotation angle in patients with hip dysplasia. These results may explain the anatomy of the knee in patients with hip dysplasia and aid in planning knee surgery.

Methods

We enrolled 73 women (146 legs, 35.6 ± 9.0 years) with bilateral hip dysplasia and 45 healthy women (90 legs, 49.0 ± 18.9 years) without lumbago, knee symptoms, or osteoarthritic findings of the knee or spine on plain radiographs. We examined the parameters affecting knee rotation angle, such as the condylar twist angle and femoral condyle measurements with a three-dimensional bone model using the correlation coefficients of each parameter.

Results

The condylar twist angle and the length of the posterior part of the lateral femoral condyle were statistically positively correlated with knee rotation angle in both the normal (condylar twist angle: r = 0.286, p = 0.007, posterolateral: r = 0.429, p < 0.001) and developmental dysplasia of the hip groups (condylar twist angle: r = 0.230, p = 0.033, posterolateral: r = 0.272, p = 0.005). Knee rotation angle had no statistical correlation with femoral neck anteversion in the developmental dysplasia of the hip group (r = 0.094, p = 0.264), but had a statistical correlation with femoral neck anteversion in the normal group (r = 0.243, p = 0.039).

Conclusions

Knee joint morphology is affected by hip dysplasia. We found that the length of the posterior part of the lateral femoral condyle was significantly positively correlated with knee rotation angle in both the normal and developmental dysplasia of the hip groups, and this finding indicates that a greater posterolateral dimension was associated with a greater knee rotation angle. These morphological knee joint differences in patients with hip dysplasia may help determine the alignment of prostheses in total knee arthroplasty.

Evaluation of anatomical pelvic parameters between normal, healthy men and women using three-dimensional computed tomography: a cross-sectional study of sex-specific and age-specific differences

Background

Sagittal spinal balance and standing posture are affected by pelvic morphology, especially pelvic incidence (PI). However, it is not difficult to identify the hip center because of overlap of the pelvis, image contrast, and soft tissue artifacts. Measurements of PI are not always suitable in all patients, especially those with osteoarthritis of the hip joint whose femoral head is nonspherical, subluxed, or dislocated. We measured PI, pelvic tilt (PT), and sacral slope (SS) as anatomical parameters using a novel three-dimensional measurement in order to compare the pelvic morphology between normal, healthy men and women.

Methods

In this cross-sectional study, we evaluated 108 Japanese subjects (55 men, 53 women) without low back or knee pain. We used the three-dimensional pelvis model adjusted to the anterior pelvic plane and measured the pelvic parameters. The subjects were stratified by age (< 50 versus ≥ 50 years) and sex. Intraobserver and interobserver reliabilities were calculated with intraclass correlation coefficients.

Results

There was no significant difference in PI, anatomical-PT, and anatomical-SS between sexes. There was a strong correlation between PI and anatomical-SS in men and women (R = 0.790 and 0.715, respectively). Values of anatomical-PT were lower, and values of anatomical-SS were greater among older subjects than among younger subjects; the value of PI was similar between younger and older subjects. Intraobserver and interobserver mean absolute differences were about 2 mm and 2°, respectively; the intraclass correlation coefficient was > 0.87.

Conclusions

We found a strong correlation between PI and anatomical-SS in men and women. This novel measurement concept may be useful to estimate PI from anatomical-SS because the measurements of PI are not always suitable in all patients, especially those with osteoarthritis of the hip joint whose femoral head is not spherical or whose femoral head is subluxed or dislocated. This is the first report to describe the relationship between PI, anatomical-PT, and anatomical-SS as morphologic parameters with a high interclass correlation coefficient for intraobserver and interobserver reliabilities.

Accuracy of acetabular cup placement using CT-based navigation in total hip arthroplasty: Comparison between obese and non-obese patients

BACKGROUND

In obese patients, malpositioning of the acetabular cup increases the risk of dislocation in total hip arthroplasty (THA). The aim of this study was to determine whether obesity affects the accuracy of acetabular cup positioning using a computed tomography (CT)-based navigation system.

METHODS

We retrospectively evaluated 226 consecutive patients who underwent cementless primary THAs assisted by the CT-based hip navigation system. We divided the patients into three groups according to body mass index (BMI) and examined the difference between preoperative planning and postoperative implantation angles from CT data.

RESULTS

There was no significant correlation between BMI and both inclination and anteversion differences (R = 0.028 and R = 0.045, respectively). There were no significant differences among the BMI < 25, 25 ≦ BMI < 30, and BMI ≧ 30 groups (p value: 0.725, 0.934, respectively); between the BMI < 25 and BMI ≧ 25 groups (p value: 0.542, 0.697, respectively); and between the BMI < 30 and BMI ≧ 30 groups with regard to inclination and anteversion (p value: 0.859, 0.456, respectively). Moreover, similar findings were observed with regard to the distance between the preoperative planning and postoperative cup positioning for the transverse, anteroposterior, and craniocaudal axes of the pelvis.

CONCLUSION

We found that the accuracy of acetabular cup placement using CT based-navigation in THA was not affected in obese patients. Therefore, THAs with a CT-based navigation system are considered useful in obese patients.

Incidence of four major types of osteoporotic fragility fractures among elderly individuals in Sado, Japan, in 2015

The aim of this study was to survey the incidence of osteoporotic fragility fractures, which include vertebral, hip, distal radius, and proximal humerus fractures, in patients ≥ 50 years of age, from 2004 to 2015, in Sado City, Japan. We examined temporal changes in the incidence of these fractures from 2010 through 2015. The incidence of vertebral (p < 0.001) and radius fractures (p = 0.001) was lower in 2015 than in 2010, with only the incidence of hip fracture (p = 0.013) being lower in 2015 than in 2004. With regard to age-specific incidences, there was a sharp increase in vertebral and hip fractures among the segment of the population 70-89 years old, with no remarkable change in the incidence of radial and humeral fractures. Pre-existing vertebral fractures were identified in 69.6% of patients with a hip fracture, 35.6% of patients with a distal radius fracture, and 55% of patients with a humeral fracture. Among patients with pre-existing vertebral fractures, 42.5% had a single fracture, whereas 57.5% had 2 or more fractures. The proportion of patients on anti-osteoporotic agents before the occurrence of fractures increased to 14.5% in 2015, compared to 4% in 2004 and 7.6% in 2010. We speculate that the increase in the use of anti-osteoporotic agents is the main reason for the declining incidence of fractures. Therefore, considering the sharp increase in hip and vertebral fractures among individuals in their mid-1970s and older, judicious use of anti-osteoporotic agents among these individuals could be useful for lowering the occurrence of these fractures.

Evaluation of pelvic morphology in female patients with developmental dysplasia of the hip using three-dimensional computed tomography: A cross-sectional study

BACKGROUND

The purpose of this study is to measure pelvic morphology with respect to the pelvic incidence, pelvic tilt, and sacral slope using 3-dimensional measurement and to compare the pelvic morphology between the normal population and women with developmental dysplasia of the hip (center-edge angle, <25°). We hypothesized that the relationship between pelvic incidence, anatomical pelvic tilt, and anatomical sacral slope would be different between normal subjects and patients with developmental dysplasia of the hip.

METHODS

We evaluated 61 healthy women without low back or knee pain and 71 patients with developmental dysplasia of the hip. We used the 3-dimensional pelvis model adjusted to the anterior pelvic plane and measured the pelvic parameters. To determine correlation, we used Pearson's coefficients. To evaluate variation, we used intraclass correlation coefficients.

RESULTS

Pelvic incidence and anatomical pelvic tilt were significantly greater by 4° in the group with developmental dysplasia of the hip than in the normal group (p = 0.026 and < 0.001, respectively). The vertical distance from hip axis to the center of the S1 endplate was significantly greater in the group with developmental dysplasia of the hip than in normal group, that is, by 8 mm (p < 0.001). There was a strong correlation between pelvic incidence and anatomical sacral slope in both groups (R = 0.707 and 0.897, respectively). The intraobserver and interobserver mean absolute differences were about 2 mm and 2°, respectively, and the intraclass correlation coefficient was >0.88.

CONCLUSION

Pelvic incidence and anatomical-pelvic tilt were significantly greater in patients with developmental dysplasia of the hip. We found a strong correlation between the pelvic incidence and anatomical sacral slope in both groups. Therefore, anatomical-sacral slope may be useful for estimating pelvic incidence because it is not easily measured, especially in patients with osteoarthritis of the hip joint.

A decrease in the number and incidence of osteoporotic hip fractures among elderly individuals in Niigata, Japan, from 2010 to 2015

We investigated the incidence of hip fracture in patients aged ≥50 years in 2015 in Niigata Prefecture, Japan. We also determined the long-term trend in hip fracture incidence from 1985 to 2015. In 2015, 3214 hip fractures occurred in Niigata Prefecture. The crude incidence rate of hip fracture was 282.7 per 100,000 persons per year (122.9 in men and 416.4 in women). The incidence of hip fracture decreased from 2010 to 2015 in all age groups except in men aged 65-69 years and women aged 60-64 years. The percentage of patients who took anti-osteoporotic medication before their hip fractures increased from 10.2% in 2010 to 14.9% in 2015. The age-specific incidence in women tended to increase until 2010, but significantly decreased from 2010 to 2015 (p < 0.001). Similarly, the incidence in men decreased from 2010 to 2015 but was not significantly different from that in 1994 (p = 0.633); this incidence had been increasing since 1999. In conclusion, a generally increasing trend was observed in the incidence of hip fractures for 30 years in both men and women in Niigata Prefecture; however, it turned into a descending trend beginning in 2010.

Bone Formation Parameters of the Biopsied Ilium Differ between Subtrochanteric and Diaphyseal Atypical Femoral Fractures in Bisphosphonate-Treated Patients

Atypical femoral fractures (AFFs) are defined as atraumatic or low-trauma fractures located in the subtrochanteric or diaphyseal sites. Long-term bisphosphonates (BPs) are administered to prevent fragility fractures in patients with primary osteoporosis or collagen diseases who are already taking glucocorticoids (GCs). Long-term BP use is one of the most important risk factors for AFFs. Its pathogenesis is characterized by severely suppressed bone turnover (SSBT), but whether the characteristics of patients are different regarding to location of fracture site remains unknown. In this study, we compared the characteristics and bone histomorphometric findings between subtrochanteric and diaphyseal sites in patients with BP-associated AFFs. Nine women with BP-associated AFFs were recruited, including 3 with systemic lupus erythematosus, 2 with rheumatoid arthritis, 2 with primary osteoporosis, 1 with polymyalgia rheumatica, and 1 with sarcoidosis. Patients were divided into the subtrochanteric group (n = 5; average age, 52 years; BP treatment, 5.9 years) and the diaphyseal group (n = 4; average age, 77 years; BP treatment, 2.6 years). Compared with the diaphyseal group, the subtrochanteric group had significantly higher daily GC doses (average, 10.9 vs. 2.3 mg/day) and significantly lower serum 25-hydroxyvitamin-D levels (17.8 vs. 25.6 ng/mL). Bone histomorphometry of the biopsied iliac bone showed SSBT in 3 cases (subtrochanteric, n = 1; diaphyseal, n = 2). Osteoid volume and trabecular thickness were significantly lower in the subtrochanteric group than in the diaphyseal group. Bone formation was inhibited more severely in subtrochanteric than in the diaphyseal group due to the higher GC doses used.

The anteroposterior axis of the tibia is adjusted to approximately a right angle to the anterior pelvic plane in the standing position in patients with hip dysplasia similar to normal subjects: a cross-sectional study

BACKGROUND

We previously described that the anteroposterior (AP) axis of the tibia is approximately perpendicular to the transverse axis of the anterior pelvic plane (APP) in the standing position in healthy subjects. The purpose of this study was to investigate the rotational alignment between the APP and clinical epicondylar axis and the AP axis of the tibia relative to pelvic coordination in the standing position in normal subjects and in women with developmental dysplasia of the hip (DDH) to aid decision making for surgeons in the alignment of implants in total hip or knee arthroplasty.

METHODS

This study included 77 Japanese women. Twenty-nine in the DDH group underwent curved periacetabular osteotomy; 48 women without lumbago and knee pain were included in the normal group. Femoral neck anteversion (FNA), condylar twist angle, and knee rotation angle were measured in femoral coordination. The angle between the femoral neck axis and clinical epicondylar axis (CEA) was measured, the transverse axis of the APP was also measured, and the angle between the AP axis of the tibia and transverse axis of the APP was calculated.

RESULTS

There was a moderate negative correlation between FNA and CEA relative to the APP. This finding indicated a trend towards greater FNA leading to more internal rotation. Knee rotation angle (KRA) relative to the APP was 1.65° ± 5.58° in the normal group and - 2.65° ± 7.57° in the DDH group. This finding indicated that the tibia AP axis was approximately perpendicular to the APP in the standing position both in the normal and DDH groups.

CONCLUSION

We found that the tibia AP axis was at approximately a right angle to the transverse axis of the APP in the standing position in both the normal and DDH groups, while the KRA was different in the normal and DDH groups. These findings may prove helpful for positional alignment investigations needed for implantation in total hip or knee arthroplasty and gait analysis.

The anteroposterior axis of the tibia is approximately perpendicular to the anterior pelvic plane in the standing position in healthy Japanese subjects

Background

We previously reported that the clinical epicondylar axis (CEA) was approximately parallel to the transverse axis of the anterior pelvic plane (APP) in the standing position in normal subjects. The purpose of this study was to investigate the rotational alignment between APP in the standing position and the anteroposterior (AP) axis of the tibia relative to pelvic coordination in normal subjects.

Methods

This study included 68 healthy Japanese, 24 males and 44 females, without lumbago and knee pain. Femoral neck anteversion (FNA), condylar twist angle, and knee rotation angle were measured in femoral coordination. The angle between the femoral neck axis and CEA transverse axis of APP was also measured, and the angle between the AP axis of the tibia and the transverse axis of APP was calculated. The mean value of knee rotation angle was 0.23° and 2.06° in male and female subjects, respectively.

Results

There was a moderate positive correlation between FNA and the femoral axis angle relative to the transverse axis of APP. The knee rotation angle relative to APP was 0.33° and 1.56° in male and female subjects, respectively, and the tibia AP axis was approximately perpendicular to the transverse axis of APP in the standing position. Regarding validation, we obtained high interclass correlation coefficients for both intraobserver and interobserver reliability.

Conclusion

We found that the knee rotation angle was almost 0° and that the tibia AP axis was approximately perpendicular to the CEA. The tibia AP axis was also approximately perpendicular to the transverse axis of the APP in standing position.

Cup implantation accuracy using the HipCOMPASS mechanical intraoperative support device

Background

While navigation systems have been developed to increase implantation accuracy in total hip arthroplasty (THA), they are not yet sufficiently versatile or commonly used. Therefore, to elevate the appeal of such systems, we have developed HipCOMPASS, a simple and effective mechanical angle indicator for use in supine THA.

Questions/purposes

How accurate is the mean cup orientation [in terms of errors in radiographic anteversion (RA) and inclination (RI)] in cases where HipCOMPASS is used for intraoperative support? Does HipCOMPASS increase this cup orientation accuracy compared to THA cases without it? Does HipCOMPASS increase mean operation time?

Methods

We measured cup orientation in 97 THA cases with HipCOMPASS and in 80 cases without it. Then we compared the angles determined in preoperative planning with the angles revealed by postoperative computed tomography (CT) for both groups. The discrepancy between them was defined as an error. Errors greater than 10° were considered outliers. Additionally, mean operative time with and without the Hip COMPASS were compared.

Results

With the use of HipCOMPASS, the mean absolute error values in radiographic anteversion and inclination were 2.9° ± 2.3° (range 0°–12.8°) and 2.9° ± 2.1° (0.1°–7.7°), respectively. In contrast, without the use of HipCOMPASS, radiographic anteversion and inclination error values were 8.8° ± 5.8° (0.1°–25.4°) and 6.1° ± 4.5° (0.2°–21.0°), respectively. Outlier occurrence rates were 1.0 % with HipCOMPASS and 48.8 % without it. Mean operative times with and without HipCOMPASS use were 109.2 ± 23.8 min (74–199 min) and 137.6 ± 40.6 min (71–298 min), respectively.

Conclusions

The study has found that HipCOMPASS dramatically increases implantation accuracy and it is also a simple and highly versatile tool that can be implemented quickly. Given its low cost in addition to its favourable accuracy, simple implementation, and short operative time, HipCOMPASS can be regarded as a very useful and effective THA support device.

Level of evidence

Retrospective comparative study, Level 3.

Mortality after hip fracture with vertebral compression fracture is poor

Due to the increasing elderly population, the prevalence of osteoporotic hip fractures in Japanese patients continues to rise. It is well established that patients with either hip fracture or both symptomatic and asymptomatic morphometric vertebral compression fracture (VCF) have a poor health prognosis compared with the general population. The purpose of this study was to retrospectively investigate vertebral fracture rates among patients with hip fracture and their influence on mortality. We examined 182 cases of osteoporotic hip fracture in patients admitted to our institution between January 2009 and May 2011. The average age at the time of fracture was 85 years. Radiographs of the lumbar spine were obtained from all of the participants and the lateral spinal radiographs were examined for evidence of VCF. The patients were classified into two groups, those with VCF and those without. A VCF was identified in approximately 78 % of the patients. The mortality rate 1 year after the hip fracture was approximately 22 % and it was significantly higher in patients with VCF. Through multivariate statistics we found that VCF, post-operative complication, loss of ambulation after operation and medication for osteoporosis were statistically significant. In other words, VCF, post-operative complication and loss of ambulation were considered to be poor prognostic factors and medication for osteoporosis was likely to improve the prognosis. We concluded that the risk of mortality after hip fracture is significantly greater in patients who also have VCF compared to patients without VCF, and that medication for osteoporosis is likely to improve prognosis.

Incidence of hip fracture in Niigata, Japan in 2004 and 2010 and the long-term trends from 1985 to 2010

We investigated the incidence of hip fracture in a population of patients ≥50 years old in 2004 and 2010 in Niigata City, Niigata Prefecture, Japan. We also investigated the long-term trends in the incidence of hip fracture from 1985 to 2010, using our previously reported survey results obtained from 1985 to 1999. In 2004 and 2010, the survey found 2,368 and 3,218 proximal femur fractures, respectively. The crude hip fracture incidence rates in 2004 and 2010 were 215.8 and 281.5 per 100,000 of population per year, respectively. For males, the incidence rates were 99.9 in 2004 and 126.3 in 2010; for females, the incidence rates were 311.0 and 410.7, respectively. In males aged 80-84 years, the incidence rate since 1999 has been decreasing, while that for males >85 years peaked in 2004. In females of all ages, the incidence rate was higher in 2010 than in all other survey periods, and in females >85 years, the incidence has increased the fastest. Additionally, the long-term changes in the age- and sex-standardized incidence each year using the 1985 population structure in Japan in females has been increasing, although it decreased in 1999. However, in males, the incidence in 2010 was not significantly different from that in 1994, although it has been increasing since 1999. Our study findings indicate that the age-specific incidence of hip fractures in the Niigata Prefecture of Japan has not plateaued in females, but that it may have done so in males; in addition, the number and incidence of hip fractures has been increasing.

[Hip Fracture--Epidemiology, Management and Liaison Service. Current status in the World and Japan]

Proximal femoral fracture in osteoporotic fracture is related to the life prognosis in the most severe. Many also report that has been reduced due to the spread of osteoporosis treatment in the world. In Japan in 1985 for the first time, we investigated all patients with hip fractures who were admitted to all hospitals with an orthopedic department in the Niigata Prefecture. We also have investigated the secular trends in the hip fracture incidence from 1985-2010. Proximal femoral fracture has been increasing in 2010, and there are no reports that have decreased. In Japan, where an aging society is to continue in the future, we need urgent countermeasure.

Three-dimensional Assessment of Femoral Head Coverage in Normal and Dysplastic Hips: A Novel Method

The acetabular coverage of the femoral head has been assessed in two-dimensions as the projected covered area or the covered angle on plain radiographs. We present a novel method of the three-dimensional assessment of femoral head coverage obtained by evaluating the covered volume of the femoral head in both normal and dysplastic hips. We also assessed the covered angles on the vertical slices passing through the center of the femoral head. The mean covered volume of the femoral head was 57.4% in normal hips and 26.6% in dysplastic hips. In dysplastic hips, the L-CE, A-CE, and P-CE angles were 7.7°, 21.8°, and 95.8°, respectively, while the acetabular angle was 27.5°. In normal hips, the CE angles were 34.0°, 56.8°, and 109.4°, respectively, while the acetabular angle was 7.2°. Our study suggests the usefulness of a novel 3D assessment for acetabular coverage of the femoral head. This assessment provided the precise 3D information necessary to diagnose hip dysplasia and assess the deficiency of acetabular coverage in these patients. Moreover, we may detect a cut-off between normal and dysplastic hips in the 3D assessment by assessing a large number of dysplastic hips both morphologically and using the new assessment.

Incidence of osteoporotic fractures in Sado, Japan in 2010

We conducted a survey of fracture incidences associated with senile osteoporosis in 2010 in Sado City, Niigata Prefecture, Japan, including compression vertebral fractures, hip fractures, distal radius fractures, and fractures of the proximal end of the humerus. We previously conducted a similar survey from 2004-2006 in Sado City. The purpose of the current study was to determine the incidence of osteoporotic fractures in Sado City in 2010 and to examine changes over time. We calculated the incidence of each fracture per 100,000 person-years based on the population of Sado City. Hip and vertebral fractures showed marked increases from 2004-2006, but a similar increase was not found from 2006-2010. The average age at injury increased in 2010 compared to 2004, except for fractures of the radius. Among the subjects with hip fractures, 14 % had a history of contralateral hip fracture. The percentage of patients taking medication for osteoporosis before injury was higher in 2010 compared with 2004, but these percentages were still only 7 and 13 % for those with subsequent hip and vertebral fractures, respectively.

Pelvic flexion measurement from lateral projection radiographs is clinically reliable

BACKGROUND

Pelvic flexion affects orientation of the acetabular cup; however, pelvic position is not static in daily activities. During THA it is difficult to know the degree of pelvic flexion with the patient in the lateral position and that position is static. However, surgeons need to appropriately determine pelvic tilt to properly insert the acetabular component.

QUESTIONS/PURPOSES

We investigated the reliability of pelvic flexion angle that was measured by manually identifying the location of the pubic symphysis and bilateral anterior superior iliac spines using synthesized lateral radiographs.

METHODS

We synthesized 49 lateral radiographs based on CT data. Each of the 49 radiographs had a unique position: 7° of varying lateral tilt and rotation in each of seven selected pelvic flexion angles. The pelvic flexion angle was measured three times by three independent observers in each position and determined the accuracy (based on the true value from the reconstructions) and reliability of the measures.

RESULTS

The measurement error was 0.1° (range, -4.8° to 4.0°). There was a tendency for errors when the pelvic flexion angle was 0° or ±5°; the errors were less when the pelvic flexion angle was ±10° or ±20°. Lateral tilt was associated with greater error than rotation. The intraclass correlation coefficient (ICC) of the average value was 0.967. For one observer, more than two measurements are necessary for the ICC to be greater than 0.8, and only one measurement was needed for two of the three observers.

CONCLUSIONS

Our data suggest measurement of pelvic flexion angle using lateral radiographs is reliable. We recommend the measurement be performed once by two observers for better reliability.

Recurrence of pelvic abscess from Panton-Valentine leukocidin-positive community-acquired ST30 methicillin-resistant Staphylococcus aureus

A 17-year-old female patient (a basketball player) suffered from recurrent pelvic abscesses from methicillin-resistant Staphylococcus aureus (MRSA). The first episode, from strain NN12, occurred in October 2004. Her cutaneous abscesses complicated into systemic progression to osteomyelitis and multifocal pelvic abscesses, adjacent to the sacroiliac joint. The second episode, abscesses at tissues adjacent to the sacroiliac joint from strain NN31A, occurred late in February 2005. The third episode, from strain NN31B, occurred on July 30, 2005, repeating the second episode. Three MRSA strains were identical in terms of genotypes (belonging to Panton-Valentine leukocidin [PVL]-positive ST30 community-acquired MRSA, CA-MRSA), pulsed-field gel electrophoresis patterns, and peptide cytolysin gene (psmα) expression levels. The three MRSA strains exhibited superior THP-1 cell invasion ability over hospital-acquired MRSA (New York/Japan clone). The data suggest that PVL-positive ST30 CA-MRSA, with high levels of cell invasion and peptide cytolysins, causes recurrence of pelvic abscesses in a healthy adolescent.

Synthesis and reactivity of allenes substituted by selenenyl groups at 1- and 3-positions

1,3-Bis(methylseleno)- and 1,3-bis(benzylseleno)-1,3-diphenylpropadienes were synthesized by reaction of Ph(2)C(3) dianion, prepared from 1,3-diphenylpropyne and n-butyllithium, with dimethyl diselenide or benzylselenocyanate in the presence of TMEDA, and reaction of the dianion with a mixture of dimethyl diselenide and benzylselenocyanate yielded 1-benzylseleno-3-methylselenoallene along with the symmetric allenes. Diselenocyclic allenes and tetraselenocyclic bisallenes were also obtained by reacting the dianion with corresponding alkane diselenocyanates. The thermal reaction of the 1,3-bis(alkylseleno)allenes mainly afforded enediynes through radical pathway, and the nine-membered cyclic allene provided intramolecular cyclization product via an intramolecular rearrangement. Heating of the cyclic bisallenes gave compounds derived from intramolecular cyclization products together with a small amount of the enediynes. Irradiation of allenes caused rearrangement of the selenenyl group to give alkynes, and the alkynes also reacted photochemically to yield the enediynes.