Different reference BMDs affect the prevalence of osteoporosis.

The T score represents the degree of deviation from the peak bone mineral density (BMD) (reference standard) in a population. Little has been investigated concerning the age at which the BMD reaches the peak value and how we should define the reference standard BMD in terms of age ranges. BMDs of 9,800 participants were analyzed from the Korean National Health and Nutrition Examination Survey database. Five reference standards were defined: (1) the reference standard of Japanese young adults provided by the dual-energy X-ray absorptiometry machine manufacturer, (2) peak BMD of the Korean population evaluated by statistical analysis (second-order polynomial regression models), (3) BMD of subjects aged 20-29 years, (4) BMD of subjects aged 20-39 years, and (5) BMD of subjects aged 30-39 years. T-scores from the five reference standards were calculated, and the prevalence of osteoporosis was evaluated and compared for males and females separately. The peak BMD in the polynomial regression model was achieved at 26 years in males and 36 years in females in the total hip, at 20 years in males and 27 years in females in the femoral neck, and at 20 years in males and 30 years in females in the lumbar spine. The prevalence of osteoporosis over the age of 50 years showed significant variation of up to two fold depending on the reference standards adopted. The age at which peak BMD was achieved was variable according to the gender and body sites. A consistent definition of peak BMD needs to be established in terms of age ranges because this could affect the prevalence of osteoporosis and healthcare policies.

Reliability and validity of the Duncan-Ely test for assessing rectus femoris spasticity in patients with cerebral palsy.

AIM: The aim of this study was to clarify the method of the Duncan-Ely test and to estimate its interobserver reliability and validity by comparing it with three-dimensional gait analysis (3DGA). METHOD: This study included 36 consecutive ambulatory patients with cerebral palsy (CP) who underwent preoperative 3DGA. The Duncan-Ely test was performed during three different velocities (slow, gravity, and fast). The interobserver reliability was assessed by three examiners. The results of the test were compared with kinematic variables derived from the gait analysis to assess the sensitivity and specificity of the test. The cut-off value was determined at the point of trade-off between the highest sensitivity and specificity. RESULTS: The intraclass correlation coefficient measuring interobserver reliability of the Duncan-Ely test was greatest during fast velocity (0.819). The sensitivity and specificity of the test during gravity velocity for knee range of motion total were 63.0% and 100% respectively, with a cut-off value of 78.3°. The sensitivity and specificity of the test during fast velocity for knee range of motion total were 66.7% and 100% respectively, with a cut-off value of 65°. INTERPRETATION: The Duncan-Ely test shows excellent reliability in fast knee-flexion velocity, and good sensitivity and specificity compared with 3DGA during physical examination as a preoperative assessment of rectus femoris spasticity in patients with CP.

Incidence and risk factors of allograft bone failure after calcaneal lengthening.

BACKGROUND: Calcaneal lengthening with allograft is frequently used for the treatment of patients with symptomatic planovalgus deformity; however, the behavior of allograft bone after calcaneal lengthening and the risk factors for graft failure are not well documented. QUESTIONS/PURPOSES: (1) What proportion of the patients treated with allograft bone had radiographic evidence of graft failure and what further procedures were performed? (2) What are the risk factors for radiographic graft failure after calcaneal lengthening? (3) What patient factors are associated with the magnitude of correction achieved after calcaneal lengthening? METHODS: Between May 2003 and January 2014, we performed 341 calcaneal lengthenings on 202 patients for planovalgus deformity, the etiology of which included idiopathic, cerebral palsy, and other neuromuscular disease. Of these, 176 patients (87%) had adequate followup for graft evaluation, defined as lateral radiographs taken before and at least 6 months after the index procedure (mean, 18 months; range, 6-100 months) and 117 patients (58%) had adequate followup for the assessment of the extent of correction, defined as weightbearing anteroposterior and lateral radiographs taken before and at least 1 year after the index procedure (mean, 24 months; range, 12-96 months). These patients' results were evaluated retrospectively. The Goldberg scoring system was chosen for demonstration of allograft behavior. A score lower than 6 at 6 months after surgery was defined as radiographic graft failure; the highest possible score was 7 points, and this represented graft incorporation with excellent reorganization of the graft and no loss of height. The patient age, sex, diagnosis, graft material, ambulatory status, and use of antiseizure medication were evaluated as possible risk factors, and we controlled for the interaction of potentially confounding variables using multivariate analysis. Additionally, six radiographic indices were analyzed for their effects on the extent of correction. RESULTS: The mean estimated Goldberg score was 6 (SD, 1.14) at 6 months after calcaneal lengthening with 11 feet (4%) classified as radiographic graft failure (Goldberg score < 6). Of these, four feet (1%) underwent reoperation using an iliac autograft bone resulting from pain and loss of correction. Multivariate analysis showed that the tricortical iliac crest allograft was superior to the patellar allograft (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.1-9.8; p = 0.038) and the possibility of radiographic graft failure was found to increase along with age (OR, 1.2; 95% CI, 1.0-1.3; p = 0.006). Radiographically, the extent of correction was found to decrease with patient age, as observed at the anteroposterior talus-first metatarsal angle (p < 0.001), lateral talocalcaneal angle (p < 0.001), lateral talus-first metatarsal angle (p < 0.001), and relative calcaneal length (p = 0.041). CONCLUSIONS: Graft failure can occur after calcaneal lengthening using allograft. Our study showed that the tricortical iliac allograft was superior to the patellar allograft, and further studies are warranted to further elucidate the effects of age on radiographic graft failure. LEVEL OF EVIDENCE: Level III, therapeutic study.

Undercorrection of planovalgus deformity after calcaneal lengthening in patients with cerebral palsy.

Calcaneal lengthening (CL) is one of the treatment options for planovalgus deformity in patients with cerebral palsy (CP). However, its indication still needs to be clarified according to the functional status of CP. The aim of this study was to investigate the radiographic outcome after CL in patients with CP and to evaluate the risk factors causing undercorrection of planovalgus deformities. We included consecutive patients with CP who underwent CL for planovalgus deformity, were followed for more than 2 years, and had preoperative and postoperative weight-bearing anteroposterior (AP) and lateral foot radiographs. Six radiographic indices were used to assess the radiographic outcome. The patient age, sex, and Gross Motor Function Classification System (GMFCS) level were evaluated as possible risk factors, and we controlled for the interaction of potentially confounding variables using multivariate analysis. A total of 44 (77 feet) patients were included in this study. The mean age of the patients at the time of surgery was 10.5±4.0 years and the mean follow-up was 5.1±2.2 years. Patients with GMFCS III/IV achieved less correction than those with GMFCS I/II in the AP talus-first metatarsal angle (P=0.001), lateral talocalcaneal angle (P=0.028), and the lateral talus-first metatarsal angle (P<0.001). The rate of undercorrection in the GMFCS III/IV group was 1.6 times higher than that in the GMFCS I/II group in the AP talus-first metatarsal angle (odds ratios: 1.6; 95% confidence interval: 1.2-2.0; P<0.001) and 1.6 times higher in the lateral talus-first metatarsal angle (odds ratios: 1.6; 95% confidence interval: 1.3-1.9; P<0.001). In GMFCS I/II patients with CP, we found CL to be an effective procedure for the correction of planovalgus foot deformities. However, in GMFCS III/IV patients with planovalgus deformities, CL appears to be insufficient on the basis of the high rate of undercorrection in these patients. For patients with GMFCS level III/IV, additional or alternative procedures should be considered to correct the deformity and maintain the correction achieved. LEVEL OF EVIDENCE: Level III, therapeutic study.

Stepwise surgical approach to equinocavovarus in patients with cerebral palsy.

This study investigated the radiologic results of a stepwise surgical approach to equinocavovarus in 24 patients with cerebral palsy and determined the extent to which each procedure affected radiographic parameters using a linear mixed model. The anteroposterior talus-first metatarsal and anteroposterior talonavicular coverage angles were improved. The calcaneal pitch angle, tibiocalcaneal angle, lateral talus-first metatarsal angle, and naviculocuboid overlap were also improved. The Dwyer sliding osteotomy affected the tibiocalcaneal angle, whereas first metatarsal dorsal wedge osteotomy improved the calcaneal pitch angle and lateral first metatarsal angle. The stepwise surgical approach is effective for correction of equinocavovarus in cerebral palsy patients.

Relationships between Isometric Muscle Strength, Gait Parameters, and Gross Motor Function Measure in Patients with Cerebral Palsy.

PURPOSE: This study investigated the correlation between isometric muscle strength, gross motor function, and gait parameters in patients with spastic cerebral palsy and to find which muscle groups play an important role for gait pattern in a flexed knee gait. MATERIALS AND METHODS: Twenty-four ambulatory patients (mean age, 10.0 years) with spastic cerebral palsy who were scheduled for single event multilevel surgery, including distal hamstring lengthening, were included. Preoperatively, peak isometric muscle strength was measured for the hip flexor, hip extensor, knee flexor, and knee extensor muscle groups using a handheld dynamometer, and three-dimensional (3D) gait analysis and gross motor function measure (GMFM) scoring were also performed. Correlations between peak isometric strength and GMFM, gait kinematics, and gait kinetics were analyzed. RESULTS: Peak isometric muscle strength of all muscle groups was not related to the GMFM score and the gross motor function classification system level. Peak isometric strength of the hip extensor and knee extensor was significantly correlated with the mean pelvic tilt (r=-0.588, p=0.003 and r=-0.436, p=0.033) and maximum pelvic obliquity (r=-0.450, p=0.031 and r=-0.419, p=0.041). There were significant correlations between peak isometric strength of the knee extensor and peak knee extensor moment in early stance (r=0.467, p=0.021) and in terminal stance (r=0.416, p=0.043). CONCLUSION: There is no correlation between muscle strength and gross motor function. However, this study showed that muscle strength, especially of the extensor muscle group of the hip and knee joints, might play a critical role in gait by stabilizing pelvic motion and decreasing energy consumption in a flexed knee gait.

Bone mineral density is not associated with musculoskeletal pain in postmenopausal Korean women aged ≥50 years.

Although many studies reported improvement of back pain after osteoporosis treatment, there is insufficient evidence to determine whether osteoporosis is painful. We investigated whether bone mineral density correlated with musculoskeletal pain in postmenopausal Korean women aged ≥50 years. Data for postmenopausal women aged ≥50 years were obtained from the fifth Korea National Health and Nutrition Examination Survey database. Demographics, Kellgren-Lawrence grade, and numeric rating scale for pain in the hip and knee joints, presence of back pain, and activity level were analyzed. Only subjects with dual-energy X-ray absorptiometry scans and hip and knee radiographs were included. Those with malignancy, pain medication use, or a history of fragility fractures were excluded. After univariate analysis, multiple linear regression analysis was performed to examine the significant factors correlated with the degree of hip and knee pain. Binary logistic regression analysis was performed to identify factors significantly associated with the presence of back pain. In total, 387 women were included in the data analysis. Age (p = 0.005) was the only significant factor correlated with the intensity of hip pain, while Kellgren-Lawrence grade (p < 0.001) was the only significant factor correlated with knee pain intensity in multiple regression analysis. Binary logistic regression analysis showed that age (p = 0.002) was the only significant factor associated with the presence of back pain. Musculoskeletal pain was not affected by or associated with the bone mineral density (BMD) of the affected body part in postmenopausal Korean women aged ≥50 years after adjusting for the degree of osteoarthritis.

Anterior knee pain in patients with cerebral palsy.

BACKGROUND: The aim of this study was to identify the risk factors for anterior knee pain in patients with cerebral palsy. METHODS: This prospective study investigated the risk factors for anterior knee pain in 127 ambulatory patients with spastic cerebral palsy in terms of walking pain, resting pain, and provocative pain. Demographic data analysis and physical examination for measuring the knee flexion contracture and unilateral and bilateral popliteal angles were performed. Patellar height was measured on radiographs, and patella alta was identified. The risk factors for anterior knee pain were analyzed using multivariate analysis with a generalized estimating equation. RESULTS: Seventy-seven patients were found to have patella alta based on the radiographic measurements (60.6%). Overall, sixteen patients (12.6%) had either unilateral or bilateral anterior knee pain. Of these, 6 patients showed a visual analogue scale (VAS) ≤ 3, 9 patients showed 3 < VAS ≤ 7, and one patient showed a VAS > 7. Age was found to be a significant risk factor for walking pain and resting pain with odds ratios (ORs) of 1.08 (95% confidence interval [CI], 1.02 to 1.14) and 1.09 (95% CI, 1.03 to 1.15), respectively. In the multivariate analysis, knee flexion contracture was a significant protective factor with an OR of 0.92 (95% CI, 0.85 to 0.98). CONCLUSIONS: Approximately 12.6% of ambulatory patients with spastic cerebral palsy were found to have anterior knee pain in our hospital-based cohort study. Age was found to be a significant risk factor for anterior knee pain while walking and resting.