Motor function is related to the lower phase angle than to muscle mass of the lower limbs in older females with hip osteoarthritis: a cross-sectional observational study.

BACKGROUND: Muscle mass and phase angle (PhA) can be measured using multi-frequency bioelectrical impedance analysis (BIA). Osteoarthritis of the hip (OAhip) causes decreased muscle mass and PhA in the deformed lower limb. However, previous studies have not accounted for the influence of sex, and thus, the relationship between muscle mass, PhA, and motor function remains unclear. This study aimed to elucidate the relationship between PhA, an index of muscle mass and quality measured using BIA, and motor function during gait and standing in female patients with OAhip. METHODS: Muscle mass and PhA of patients with OAhip were measured using BIA. Motor function was evaluated using the Timed Up and Go test, ground reaction/weight, rate of force development/weight, and load ratio between the osteoarthritic (OA) and contralateral sides when standing up. The difference between the OA side and the contralateral lower limb was tested to clarify the characteristics of the deformed lower limb. The relationship between each motor function was determined using a partial correlation coefficient with age as a control variable and multiple regression analysis with each motor function as the dependent variable and age, OA-side muscle mass/body weight ratio, and PhA as independent variables. RESULTS: This study involved 60 patients with OAhip (age 65.6 ± 7.6 years, height 154.2 ± 6.0 cm, weight 56.8 ± 10.5 kg) scheduled for unilateral total hip arthroplasty. Muscle mass, PhA, and lower limb load ratio were significantly decreased in the lower limbs on the OA side. Furthermore, using a partial correlation coefficient with age as a control variable, PhA showed significant correlations with motor functions related to standing up and walking, and multiple regression analysis revealed that PhA was independently related to each motor function. CONCLUSIONS: Evaluation and interventions that consider muscle quality rather than muscle mass are important.

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.

Accuracy of ZedView, the Software for Three-Dimensional Measurement and Preoperative Planning: A Basic Study.

Background and Objectives: In the field of orthopedic surgery, novel techniques of three-dimensional shape modeling using two-dimensional tomographic images are used for bone-shape measurements, preoperative planning in joint-replacement surgery, and postoperative evaluation. ZedView® (three-dimensional measurement instrument and preoperative-planning software) had previously been developed. Our group is also using ZedView® for preoperative planning and postoperative evaluation for more accurate implant placement and osteotomy. This study aimed to evaluate the measurement error in this software in comparison to a three-dimensional measuring instrument (3DMI) using human bones. Materials and Methods: The study was conducted using three bones from cadavers: the pelvic bone, femur, and tibia. Three markers were attached to each bone. Study 1: The bones with markers were fixed on the 3DMI. For each bone, the coordinates of the center point of the markers were measured, and the distances and angles between these three points were calculated and defined as "true values." Study 2: The posterior surface of the femur was placed face down on the 3DMI, and the distances from the table to the center of each marker were measured and defined as "true values." In each study, the same bone was imaged using computed tomography, measured with this software, and the measurement error from the corresponding "true values" was calculated. Results: Study 1: The mean diameter of the same marker using the 3DMI was 23.951 ± 0.055 mm. Comparisons between measurements using the 3DMI and this software revealed that the mean error in length was <0.3 mm, and the error in angle was <0.25°. Study 2: In the bones adjusted to the retrocondylar plane with the 3DMI and this software, the average error in the distance from the planes to each marker was 0.43 (0.32-0.58) mm. Conclusion: This surgical planning software could measure the distance and angle between the centers of the markers with high accuracy; therefore, this is very useful for pre- and postoperative evaluation.

Minimum ten-year outcome of a triple-tapered femoral stem implanted with line-to-line cementing technique.

BACKGROUND: A triple-tapered polished femoral stem was implanted with line-to-line cementing technique. The purpose of this study was to determine the survivorship, loosening rate, stem subsidence, radiologic changes and clinical outcomes in the minimum 10-year follow-up. METHODS: This was a retrospective study done in three institutes. Finally, 118 hips in 97 patients could be followed-up at the mean follow-up period of 126.3 months. The survivorship, radiological and clinical outcomes were investigated. RESULTS: Radiologically, 107 hips (90.7%) were categorized to Barrack cementing grade A, and 108 stems (91.5%) were inserted in neutral position. All hips were not loose and were not revised due to any reason. Survival with revision for any reason as the endpoint was 100% after 10 years. At the last follow-up, the mean subsidence was 0.43 mm, and the subsidence was less than 1 mm in 110 hips (93.2%). JOA hip score improved from 42.7 ± 8.9 points preoperatively to 92.8 ± 6.8 points at the last follow-up. No patient complained thigh pain. CONCLUSIONS: Line-to-line cementing technique with use of a triple-tapered polished stem was effective to achieve good cementation quality and centralization of the stem. The subsidence was small, and the minimum 10-year results were excellent without any failures related to the stem. TRIAL REGISTRATION: Retrospectively registered.

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.

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.

Investigation on the measurement sites of the cross-sectional areas of the gluteus maximus and gluteus medius.

PURPOSES: To verify the relationship between muscle volume and muscular strength of different cross-sectional areas (CSAs) of the gluteus maximus and medius, and to clarify the effective evaluation index. METHODS: Twenty healthy adults were enrolled in this cross-sectional study. Magnetic resonance images were evaluated, and CSAs of the gluteus maximus and medius were calculated. Calculation sites were the peak CSA, lowest end of the sacroiliac joint CSA, and just above the femoral head CSA. Muscle volume and muscular strength were measured. The correlation between muscular CSA, muscle volume, and muscular strength was verified using Pearson's correlation coefficient (p < 0.05). One-way analysis of variance and the Tukey-Kramer test were used to verify differences in each CSA (p < 0.05). RESULTS: A significantly positive correlation was found between muscular CSA, muscle volume, and muscular strength of both muscles (p < 0.05). For the gluteus maximus, the muscular CSA calculated just above the femoral head showed a significantly larger value than that calculated at the lowest end of the sacroiliac joint (p < 0.05). For the gluteus medius, the peak CSA and muscular CSA calculated at the lowest end of the sacroiliac joint were significantly larger than that calculated just above the femoral head (p < 0.05). CONCLUSIONS: The maximum CSA of the gluteus maximus was found just above the femoral head and that of the gluteus medius was near the lowest end of the sacroiliac joint; hence, CSAs should be calculated at these sites. The CSA reflected muscle volume and strength.

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.

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.

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.

Effects of weekly and fortnightly therapeutic exercise on physical function and health-related quality of life in individuals with hip osteoarthritis.

BACKGROUND: Most previous studies on the effects of therapeutic exercise on osteoarthritis (OA) of the hip joint included participants with knee OA or postoperative participants. Moreover, although some systematic reviews recommend therapeutic exercise for hip OA, a consensus on the effective interventional frequency has not been reached. This study aimed to investigate the effects of therapeutic exercise performed at different frequencies on physical function and health-related quality of life in participants with hip OA. METHODS: Individuals diagnosed with hip OA (36 women, age 42-79 years; 19 in 2009 and 17 in 2010) were recruited from the cooperating medical institutions. They were divided into two groups depending on the frequency of therapeutic exercise: fortnightly in 2009 (fortnightly group) and weekly in 2010 (weekly group). Participants in each group performed the same land-based and aquatic exercises on the same day for a total of ten sessions. Muscle strength of the lower extremity, "timed up and go" (TUG), time of one-leg standing with open eyes (TOLS), Harris Hip Score, and scores of the Medical Outcomes Survey Short Form-36 questionnaire, were measured before and after interventions. RESULTS: The fortnightly group had no significant changes in lower-extremity muscle strength following intervention, but the strength of all muscles in the weekly group improved significantly after intervention. Further, in both groups, TUG and TOLS of the worse side of the hip joint significantly improved after interventions. CONCLUSIONS: Weekly exercise improves muscle strength of the lower extremity and may therefore be an effective interventional technique for managing hip OA. In addition, in persons with hip OA, therapeutic exercise consisting of both land- and water-based exercises markedly improved physical function.

[Treatment of femoral neck fracture--preference to internal fixation].

In the guidelines for the treatment of femoral neck fracture, prosthetic replacement is recommended in displaced one and internal fixation is in undisplaced one. However, in the long view, survived femoral head after internal fixation can be superior to prosthesis which will deteriorate as time goes by. Surgical method should be considered not only by type of fracture but general status of the patient.

Formulas for estimating living stature based on bony pelvic measurements reconstructed from computed tomography images.

Introduction: A major challenge in anthropology is the estimation of human stature based on human bones since the stature of cadavers is slightly different from that of living humans. This study aimed to investigate the feasibility of estimating living stature in Japanese subjects based on sacral and coccygeal lengths as measured on three-dimensional (3D) models of the femur and pelvis reconstructed from cross-sectional computed tomography (CT) images. Subjects and methods: For this cross-sectional study, 106 healthy Japanese subjects (54 men and 52 women) were recruited. We measured the distances from the anterosuperior iliac spine (ASIS) to the most posterior point of the ischial spine (IS) (ASIS-IS), and from the ASIS to the most inferior point of the ischial tuberosity (IT) (ASIS-IT) on 3D bone models reconstructed from multi-slice CT images. Correlations of living stature with ASIS-IS and/or ASIS-IT on the left and right sides of the pelvis were evaluated. Multiple regression equations were derived and used as formulas for living stature estimation. Results: In men, living stature had strong correlations with ASIS-IS + ASIS-IT on both the left and right sides; Pearson's correlation coefficients were 0.717 and 0.706, respectively. In contrast, in women, living stature showed stronger correlations with all of the studied parameters; Pearson's correlation coefficients were highest for ASIS-IS + ASIS-IT on both the left and right sides (r = 0.753 and 0.744, respectively) compared with those in men. Formulas based on ASIS-IS + ASIS-IT provided the best estimation in both men and women, while ASIS-IS alone demonstrated a better estimation than ASIS-IT on both the left and right sides. Conclusions: This study revealed that ASIS-IS and ASIS-IT measured from CT images were reliable predictors of living stature in the Japanese population. Our estimation formulas were derived from measurements of living stature that were not affected by the physiological changes observed in cadavers. To the best of our knowledge, this is the first study to derive estimation formulas based on living stature. Our method may be useful in the identification of disaster victims, wherein long bones are usually not found intact but pelvic bones are. Furthermore, the findings could be relevant to the field of anthropology for estimating living stature.

Three-dimensional lower extremity alignment in the weight-bearing standing position in healthy elderly subjects.

BACKGROUND: Although assessment of lower extremity alignment is important for the treatment and evaluation of diseases that present with malalignment of the lower extremity, it has generally been performed using only plain radiographs seen in two dimensions (2D). In addition, there is no consensus regarding the criteria for quantitative three-dimensional (3D) evaluation of the relative angle between the femur and tibia. The purpose of this study was to establish assessment methods and criteria for quantitatively evaluating lower extremity alignment in 3D and to obtain reference data from normal elderly subjects. METHODS: The normal alignment of 82 limbs of 45 healthy elderly subjects (24 women, 21 men; mean age 65 years, range 60-81 years) was analyzed in 3D with regard to flexion, adduction-abduction, and rotational angle of the knee in the weight-bearing, standing position. The obtained computed tomography (CT) and biplanar computed radiography (CR) data were used to define several anatomical axes of the femur and tibia as references. RESULTS: In the sagittal plane, the mean extension-flexion angle was significantly more recurvatum in women than in men. In the coronal plane, the mean 3D hip-knee-ankle angle was more varus by several degrees in this Japanese series than that in a Caucasian series reported previously. Regarding rotational alignment, the mean angle between the anteroposterior axis of the tibia and the transepicondylar axis of the femur in this series was slightly larger (externally rotated) than that of previously reported Japanese series examined in the supine position. CONCLUSIONS: These data are believed to represent important references for 3D evaluation of morbid lower extremity alignment in the weight-bearing, standing position and are important for biomechanical research (e.g., 3D analyses of knee kinematics) because the relative angles between the femur and tibia are assessed three-dimensionally.

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.

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.

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.