Electronic monitoring of orthopedic brace compliance

Purpose

Brace compliance measurement in adolescent idiopathic scoliosis (AIS) has been the subject of a few recent studies. Various sensors have been developed to measure compliance. We have developed a temperature-based data logger—the Cricket—specifically for scoliosis braces, with associated custom software, that is embedded directly in the brace. The purpose of this study was to analyze patterns of brace wear and patient compliance among children with AIS using the Cricket.

Methods

Fifty-five AIS patients prescribed various brace-time regimens were monitored using the Cricket. All subjects were treated with the Wilmington brace. The compliance rate for each group was determined.

Results

Overall compliance among subjects was 69.9 ± 31.5 %. Only 14.5 % met or exceeded prescribed brace time. This is consistent with previous compliance monitoring results.

Conclusion

The results of this study objectively show the difference between prescribed and actual brace wear time and reaffirm the Cricket sensor as an accurate and comfortable brace-monitoring device.     

Periprosthetic bone mineral density with a cementless triple tapered stem is dependent on daily activity

Purpose

Periprosthetic bone loss around the femoral stem is frequently found after total hip arthroplasty. We have shown that periprosthetic bone mineral density (BMD) loss using the triple tapered stem is consistently much less in comparison with the straight type component. In this study, we compared periprosthetic BMD change with clinical factors.

Methods

Postoperative dual-energy X-ray absorptiometry was evaluated at follow-up. BMD was determined based on seven Gruen zones. We further compared BMD with clinical examination: body mass index (BMI), age, Harris hip score (HHS) or University of California at Los Angeles (UCLA) activity rating score.

Results

Periprosthetic BMD loss of the triple tapered stem was maintained. Especially, BMD in Gruen zone 1 which was maintained at 96% in comparison with the straight tapered stem. We compared the BMD change with clinical factors. There is no correlation between BMD and BMI, age or HHS. However, we found significant correlation between BMD and UCLA activity rating score in Gruen zones 1 and 2 of the triple tapered stem. Further, the correlation coefficient was increased at 48 months in comparison with 24 months.

Conclusion

The cementless triple tapered stem maintains periprosthetic bone mineral density. Activity may reflect improving periprosthetic bone quality after THA using a triple tapered stem.

Electronic supplementary material

The online version of this article (doi:10.1007/s00264-011-1407-3) contains supplementary material, which is available to authorized users.     

Bone mineral density changes of the proximal tibia after revision total knee arthroplasty. A randomised study with the use of porous tantalum metaphyseal cones

Purpose

Forty patients were enrolled in a prospective randomised study using conventional method or “Trabecular Metal Cone” (TM Cone) (Zimmer inc., Warsaw, USA) for reconstruction of bone loss of the proximal tibia during revision total knee arthroplasty (rTKA). The aim was to evaluate changes in bone mineral density (BMD) at the proximal tibia.

Material and methods

Thirty-six patients [median 67 years (range: 40–85 years)] received rTKA with NexGen® (Zimmer Warsaw, USA) revision system. Knee Society´s Knee Scoring System and the Anderson Orthopaedic Research Institute (AORI) bone classification was used. Changes in BMD were measured by dual energy X-ray absorptiometry (DEXA).

Results

Knee and function score improved in both groups. No significant changes between the groups were found. Changes in BMD within the two groups were quite similar. Overall decreases in BMD of 0.1 - 5.4 % were found in both groups (ROI 1–6) postoperative to 12 months of follow-up, except that ROI 7 showed an increase in BMD (0.8 - 1.3 %). After 24 months of follow-up, an increase in BMD was found along the stem (ROI 2–5) of 1.9 - 6.3 % , with significant changes in the TM Cone Group (ROI 3, 4, 5) . No significant changes in BMD between the groups were found.

Conclusions

The bone remodelling pattern was almost the same in the two groups after two years.     

Factors associated with the success of the Rigo System Chêneau brace in treating mild to moderate adolescent idiopathic scoliosis

Background

Adolescent idiopathic scoliosis (AIS) is the most prevalent spine deformity within the pediatric population. Orthosis is the mainstay of conservative treatment for mild to moderate AIS. The Rigo System Chêneau (RSC) brace is a custom-made thoracolumbar sacral orthosis (TLSO) based on a three-dimensional correction concept. The purpose of this study was to identify factors that could predict the therapeutic success/failure of the RSC brace.

Materials and methods

A retrospective cohort study was performed on all consecutive patients according to the Scoliosis Research Society (SRS) criteria for the success of conservative treatment. Participants had a 2-year follow-up beyond the termination of brace treatment. All patients were treated with the RSC orthotic device.

Results

Ninety-three patients met the inclusion criteria. At treatment onset, their average age was 12.9 years, average Cobb angle 31.97°, Risser score 1.07, and the mean angle of thoracic rotation (ATR) was 10.2°. The mean brace treatment period was 36 months. Treatment was successful in 83.8 % of these patients (n = 79). The average final Cobb angle was 28.97°, Risser score 4.88, and ATR 8.09°. The pre-treatment factors associated with the success of applying the RSC brace were a high Risser score [odds ratio (OR) = 2.97, 95 % confidence interval [CI] 1.18–7.44; p = 0.02), a low Cobb angle (OR = 0.92, 95 % CI 0.85–0.99; p = 0.02), and low ATR (OR = 0.86, 95 % CI 0.75–0.99; p = 0.04).

Conclusions

The treatment of mild to moderate AIS with the RSC brace provides excellent clinical results. Its added benefit is enabling a three-dimensional correction of a three-dimensional deformity. Pre-treatment high Risser score, low Cobb angles, and low ATRs are associated with treatment success.

Level of evidence

Retrospective analysis, Level III.     

Evolution of the curve patterns during brace treatment for adolescent idiopathic scoliosis

Summary of background data

The curve pattern of idiopathic scoliosis is important for making decisions concerning bracing. However, whether the curve pattern changes during brace treatment have not been fully documented. The aim of this study was to investigate the changes of curve pattern during brace treatment in skeletally immature patients with adolescent idiopathic scoliosis (AIS).

Methods

From January 2002 to January 2011, AIS patients treated with a Boston or Milwaukee brace were recruited after meeting the following inclusion criteria: older than 10 years of age at initiation of bracing; having a Cobb angle of 25°–40°; with a Risser sign 0–2; being regularly followed until the weaning of brace or the necessity of surgical treatment; and without history of previous treatment. A total of 130 female and 11 male AIS patients were included. The mean age was 12.9 years at initiation of bracing, and the female patients were, on average, 2.7 months past menarche. The mean follow-up period was 2.6 years (range 1.0–5.5 years). The definitions of changes in curve patterns were divided into four categories as follows: (1) shift of the apex of the main curve; (2) change in the curve span of more than two vertebrae; (3) change in the main curve type with regard to the apex location; and (4) change of curve direction. The patients were divided into two groups. Group A was comprised of patients who had experienced one or more categories of curve pattern changes, and Group B was comprised of those who had not.

Results

Of these 39 patients, 14 had apex shifting, 2 underwent curve span changes, 22 experienced changes in the main curve type, and one female had both changes in the apex and curve span. At the initiation of bracing, patients in Group A demonstrated significantly lower menarchal status (P = 0.018) and lower Risser grade (P = 0.025) than those in Group B. The difference in the percentage of patients who underwent Boston bracing between the two groups was statistically significant (41.5 % for Group A vs. 24.0 % for Group B, P = 0.023).

Conclusion

Changes in curve pattern can occur during brace treatment. Patients with less skeletal maturity and those treated with a Boston brace are more susceptible to this phenomenon.     

Evaluation of bone mineral loss in patients with chronic traumatic spinal cord injury in Iran

Objectives

We described the associations between demographic and injury-related factors on bone mineral density (BMD) of the spine and the hip among adult patients with chronic spinal cord injury (SCI).

Design

BMD in spinal and femoral bone sites were assessed. Multivariate analysis was performed to evaluate the relationship between anthropometric and injury-related factors with BMD. Serum level and amount of dietary intake of calcium, phosphor, and 25-hydroxy vitamin D were measured.

Setting

A referral tertiary rehabilitation center in Iran.

Participants

Patients with SCI who had no previous history of endocrine disorders and were not on specific medications entered the investigation. Those with non-traumatic SCI, pregnant, or with substance dependency were excluded as well.

Interventions

No interventions were applied.

Main study outcome measures

Dual X-ray absorptiometry was performed to estimate BMD. Body mass index was positively associated with higher femoral (P < 0.01, r = 0.56) and hip (P < 0.0001, r = 0.82) BMD only in female participants. The high prevalence of vitamin D deficiency (60%) was noticeable.

Results

Older male patients revealed lower BMD only in spinal vertebrae (P < 0.02, r = −0.21). A significant higher BMD loss in lumbar vertebras in male patients with complete spinal cord lesion (P < 0.009) was detected. Spinal reduction of BMD was more severe when the level of injury was above T6 (P < 0.02).

Conclusion

Along with the clarification of age, gender, post injury duration, and the other factors'' effect on the BMD in the SCI patients, here we have also shown the noticeable prevalence of the 25-hydoxy vitamin D deficiency in these patients which needs attention.     

Very short-term effect of brace wearing on gait in adolescent idiopathic scoliosis girls

Purpose

Adolescent idiopathic scoliotic (AIS) deformity induces excessive oxygen consumption correlated to a bilateral increase of lumbo-pelvic muscles timing activity (EMG) during gait. Wearing a brace, the usual treatment for AIS, by supporting the spine and the pelvis, would generate lumbo-pelvic muscular relaxation and consequently reduce excessive oxygen consumption. The purpose of this study was to evaluate the short-term effect of bracing on gait biomechanics in scoliotic spine when compared with normal braced spine.

Methods

Thirteen healthy volunteers were compared to 13 AIS girls. In both samples, gait analysis was assessed using a three-dimensional motion analysis, including synchronous kinematic, electromyographic, mechanical and energy measurements, first without brace, then wearing a brace.

Results

For scoliotic patients, comparison of in-brace and out-brace situations revealed a significant decrease of frontal pelvis (p < 0.001), hip (p < 0.001) and shoulder (p = 0.004) motion in brace associated with a significant reduction of pelvis rotation (p = 0.003). However, the brace did not change significantly the lumbo-pelvic muscle activity duration (EMG) or the mechanical and energetic parameters. Transversal pelvis motion was reduced by 39 % (p = 0.04), frontal hip and shoulder motions by 23 % (p = 0.004) and 30 % (p = 0.01) respectively, and energy cost of walking remained increased by 37 % in braced AIS girls relatively to braced healthy subjects. Mechanical and electromyographic variables were not significantly different between the two braced populations during gait except for the gluteus medius muscle that showed bilaterally an increase of duration of electrical activity in healthy subjects and contrarily a decrease in AIS patients (healthy: −3.5 ± 9.6 % of gait cycle vs. scoliotic: 3.7 ± 7.7 % of gait cycle; p = 0.04).

Conclusions

Bracing changed neither the oxygen consumption nor the timing of the lumbo-pelvic muscles activity in both groups during gait. However, in brace the timing activity of bilateral gluteus medius muscles tended to decrease in AIS patients and increase in healthy subjects. Moreover, braced AIS patients had more restricted frontal hips and shoulder motion as well as pelvis rotation than braced healthy subjects.     

Underestimation of Bone Loss of the Spine With Posterior-Anterior Dual-Energy X-Ray Absorptiometry in Patients With Spinal Cord Injury

Background:

Bone mineral density (BMD) of the lumbar spine (L-spine) has been reported to be normal by routine posterior-anterior (PA) bone density imaging in patients with chronic spinal cord injury (SCI).

Objective:

To determine BMD of the L-spine by PA and lateral (LAT) dual-energy radiographic absorptiometry (DXA) in patients with chronic SCI.

Design:

Prospective study.

Setting:

Veterans Affairs Medical Center and a private rehabilitation facility.

Methods:

Measurements of the PA and LAT L-spine and hip were performed in 15 patients with SCI: 9 with tetraplegia and 6 with paraplegia. The DXA (GE Lunar Advance DXA) images were obtained using standard software. Results are reported as mean ± SD.

Results:

The mean age was 35 ± 15 years (range  =  20–62 years), and the duration of injury was 57 ± 74 months (range  =  3–240 months). T- and Z-scores were lower for the LAT L-spine than those for PA L-spine (T-scores L2: −0.7 ± 1.2 vs 0.0 ± 1.4, P < 0.01; L3: −0.9 ± 1.6 vs 0.3 ± 1.3, P < 0.002; L2-L3: −0.8 ± 1.3 vs 0.2 ± 1.3, P < 0.001; Z-scores L2: −0.3 ± 1.1 vs 0.2 ± 1.2, P < 0.05; L3: −0.6 ± 1.3 vs 0.5 ± 1.3, P < 0.01; L2-L3: −0.4 ± 1.1 vs 0.4 ± 1.2, P < 0.005). The T- and Z-scores for the total hip (−1.1 ± 1.0 and −1.0 ± 1.0, respectively) and L2-L3 LAT L-spine demonstrated remarkable similarity, whereas the L2-L3 PA L-spine scores were not reduced. Bone mineral density of the LAT L-spine, but not the PA L-spine, was significantly reduced with increasing duration of injury.

Conclusions:

Individuals with SCI may have bone loss of the L-spine that is evident on LAT DXA that may be misdiagnosed by PA DXA, underestimating the potential risk of fracture.     

The Effect of Bisphosphonates on Bone Mineral Density in Metastatic Prostate Cancer Patients Who Are Treated with Anti-Androgen Drugs and Radiotherapy

Objective

To evaluate the potential effect of bisphosphonates on bone mineral density (BMD) in patients who are treated with anti-androgen drugs and radiotherapy for metastatic prostate cancer.

Materials and Methods

The data of 31 patients with metastatic prostate cancer who were treated with anti-androgen drugs and radiotherapy during a 1-year period were retrospectively reviewed. Patients were divided in 2 groups, in which 17 patients in group 1 were treated with zoledronic acid (4 mg/month, intravenous) and 14 patients in group 2 who did not receive zoledronic acid. BMD was measured before the treatment and at the end of the 1st year by dual energy X-ray absorptiometry. Statistical analyses were performed with the T test.

Results

Mean age of the patients was 71.42 ± 6.7(range 59-85) years. A significant increase was noted for pelvic bone, femoral neck, and lumbar vertebrae t scores when pretreatment and 1st year measurements were compared in group 1 (p < 0.05). In group 2 a significant decrease was noted for pelvic bone and femoral neck t scores at the end of the 1st year (p < 0.05). A significant increase was noted for pelvic bone and femoral neck follow-up in BMD values at the end of the 1st year compared to initial measurements in group 1. A significant decrease was noted for lumbar vertebrae follow-up in BMD values at the end of the 1st year when compared to initial values in group 2.

Conclusion

Zoledronic acid significantly increases BMD and delays unfavorable outcomes for bones in men who are treated with anti-androgen drugs and radiotherapy for metastatic prostate cancer.Key Words: Metastatic prostate cancer, Osteoporosis, Radiotherapy, Bisphosphonate therapy     

Knee flexion influences periprosthetic BMD measurement in the tibia: Suggestions for a reproducible clinical scan protocol

Background and purpose

The quality and quantity of bone is important for the success of joint prostheses and may be monitored by dual energy X-ray absorptiometry (DXA). Available protocols suggest that the knee should be positioned in full extension. This is not possible for most patients in the first days after surgery; however, deficits in extension normalize with rehabilitation. Individual knee flexion between the baseline and follow-up investigations may therefore be different. We investigated the sensitivity of bone mineral density (BMD) measurements to knee flexion in a phantom study and in patients. We suggest a protocol for clinical use.

Methods

2 phantom tibial bones with tibia components were secured in a clamp and BMD measurements were repeated 5 times at every 5° change in flexion from 0° to 20°. For clinical use, a soft foam positioner was produced, in which the lower leg could be placed in neutral rotation and with the knee in approximately 25° of flexion. The clinical repeatability was tested with double examinations in 38 patients. We investigated 3 regions of interest (ROIs) below the tibial plateau.

Results

In the phantom study, just 5° of flexion was found to change the measured mean BMD. The reproducibility of clinical measurements (coefficient of variation) in the 3 ROIs assessed ranged from 1.8% to 3.7% for the anteroposterior scans, and from 3.4% to 6.2% for the lateral scans.

Interpretation

Knee flexion does affect the measured periprosthetic tibial BMD, and knee flexion should be the same at all clinical follow-ups. The protocol and soft foam positioner that we suggest permit precise and reliable assessment of BMD in the proximal tibia and they can be used in clinical work.     

Bone mineral density is not related to heterotopic ossification after total hip arthroplasty

Purpose

Heterotopic ossification (HO) after total hip arthroplasty (THA) is a frequent complication that compromises the success of this procedure; however, its precise pathogenesis is unknown. Patient-related risk factors have previously been investigated to predict patients likely to have HO. In this study, we compared bone mineral density (BMD) between patients with and without HO after THA.

Methods

We measured BMD of the lumbar spine, radius, and calcaneus using dual-energy X-ray absorptiometry in 98 females who were scheduled to undergo THA. Radiographs were graded for the presence of HO according to the criteria of Brooker at a minimum follow-up of two years following THA. BMD were compared between those with HO and those without.

Results

In total, HO was observed in 20 of 98 hips. There were no significant differences in age, height, weight, body mass index, and pre-operative total hip score between the HO and non-HO groups. No significant difference was observed in BMD of the lumbar spine, distal radius, mid-radius, and calcaneus between the two groups.

Conclusions

Our findings suggest that generalized BMD is not related to the occurrence of HO after THA in women.     

Bone mineral density of the femoral neck in resurfacing hip arthroplasty: Precision of DXA biased by region of interest and rotation of the hip

Background and purpose

Resurfacing total hip arthroplasty (RTHA) may preserve the femoral neck bone stock postoperatively. Bone mineral density (BMD) may be affected by the hip position, which might bias longitudinal studies. We investigated the dependency of BMD precision on type of ROI and hip position.

Method

We DXA-scanned the femoral neck of 15 resurfacing patients twice with the hip in 3 different rotations: 15° internal, neutral, and 15° external. For each position, BMD was analyzed with 3 surface area models. One model measured BMD in the total femoral neck, the second model divided the neck in two, and the third model had 6 divisions.

Results

When all hip positions were pooled, average coefficients of variation (CVs) of 3.1%, 3.6%, and 4.6% were found in the 1-, 2-, and 6-region models, respectively. The externally rotated hip position was less reproducible. When rotating in increments of 15° or 30°, the average CVs rose to 7.2%, 7.3%, and 12% in the 3 models. Rotation affected the precision most in the model that divided the neck in 6 subregions, predominantly in the lateral and distal regions. For larger-region models, some rotation could be allowed without compromising the precision.

Interpretation

If hip rotation is strictly controlled, DXA can reliably provide detailed topographical information about the BMD changes around an RTHA. As rotation strongly affects the precision of the BMD measurements in small regions, we suggest that a less detailed model should be used for analysis in studies where the leg position has not been firmly controlled.     

One-screw fixation provides similar stability to that of two-screw fixation for type II dens fractures

Background

Anterior screw fixation has been widely adopted for the treatment of Type II dens fractures. However, there is still controversy regarding whether one- or two-screw fixation is more appropriate.

Questions/Purposes

We addressed three questions: (1) Do one- and two-screw fixation techniques differ regarding shear stiffness and rotational stiffness? (2) Can shear stiffness and rotational stiffness after screw fixation be restored to normal? (3) Does stiffness after screw fixation correlate with bone mineral density (BMD)?

Methods

We randomly assigned 14 fresh axes into two groups (seven axes each): one receiving one-screw fixation and another receiving two-screw fixation. Shear and torsional stiffness were measured using a nondestructive low-load test in six directions. A transverse osteotomy then was created at the base of the dens and fixed using one or two screws. Shear and torsional stiffness were tested again under the same testing conditions.

Results

Mean stiffness in all directions after screw fixation was similar in both groups. The stiffness after one- and two-screw fixation was not restored to normal: the mean shear stiffness restored ratio was less than 50% and the mean torsional stiffness restored ratio was less than 6% in both groups. BMD did not correlate with mean stiffness after screw fixation in both groups.

Conclusions

One- and two-screw fixation for Type II dens fractures provide similar stability but neither restores normal shear or torsional stiffness.

Clinical Relevance

One-screw fixation might be used as an alternative to two-screw fixation. Assumed BMD should not influence surgical decision making.     

Association of rs11190870 near LBX1 with adolescent idiopathic scoliosis susceptibility in a Han Chinese population

Purpose

To investigate whether rs11190870 near LBX1 correlates with the susceptibility or curve progression of adolescent idiopathic scoliosis (AIS) in a Han Chinese population.

Methods

A total of 949 AIS patients and 976 age-matched healthy controls were recruited. All the subjects were genotyped using the PCR-based invader assay. Case–control study and case-only study were performed to define the contribution of rs11190870 to predisposition and curve severity of AIS. Additionally, we further conducted a meta-analysis of the study findings together with those of previously reported studies.

Results

A significant association of rs11190870 with AIS was observed in the Han Chinese population (P = 1.8 × 10⁻⁹; odd ratio = 1.51; 95 % confidence interval = 1.33–1.71), and AIS patients with TT genotype had a larger Cobb angle than those with TC or CC genotype (P = 0.005). The meta-analysis confirmed that the positive association of this SNP with AIS in the East Asian population.

Conclusions

The SNP rs11190870 near LBX1 is associated with both susceptibility and curve progression of AIS.     

Influence of Insurance Benefit Criteria on the Administration Rate of Osteoporosis Drugs in Postmenopausal Females

Background

Preventive measures need to be implemented to lower the incidence of osteoporotic fractures. Osteoporotic fractures increase morbidity and mortality as well as impose a socioeconomic burden; however, current research is limited to the administration rates of osteoporosis drugs for Korean postmenopausal females.

Methods

This study represents a nationwide, observational, and cross-sectional survey that investigates the administration rates of osteoporosis drugs based upon a bone mineral density (BMD) test performed on Korean postmenopausal patients who visited outpatient orthopedic clinics. BMD test results were examined in postmenopausal female patients (50 to 80 years of age); subsequently, the patients were classified into an osteoporosis group, osteopenia group, and normal group. The administration rates of osteoporosis drugs and bisphosphonates were then analyzed. The osteoporosis group was subdivided into a T-score less than -3.0 group and a T-score between -3.0 and -2.5 group that were separately analyzed.

Results

Based on the lumbar spine BMD, the rate of administration of osteoporosis drugs in the osteoporosis group was 42.1%, which was significantly higher compared to the osteopenia group or normal group. A significantly low bone mineral density was observed in patients who were administered bisphosphonates. Based on the lumbar spine BMD, the administration rate of osteoporosis drugs in the group with a T-score between -3.0 and -2.5 (34.2%) was significantly lower than the group with a T-score less that -3.0 (46.2%). The bisphosphonate administration rate was also significantly low; however, the administration rate for osteoporosis drugs was significantly lower than that of the osteopenia group.

Conclusions

Only about 40% of Korean postmenopausal female patients with osteoporosis were administered osteoporosis drugs. The administration rate in patients with a T-score between -3.0 and -2.5 was particularly low and active treatment to prevent osteoporotic fractures is required in this group.     

The cementless Bicontact? stem in a prospective dual-energy X-ray absorptiometry study

Purpose

The cementless Bicontact® total hip arthroplasty (THA) system (AESCULAP AG, Tuttlingen, Germany) was introduced in 1986/1987 and has been in successful clinical use in an unaltered form up to today. Although good long-term results with the Bicontact® stem have been published, it is questionable whether the implant provides the criteria for a state-of-the-art stem regarding proximal bone stock preservation. The purpose of the study was to monitor the periprosthetic bone mineral density (BMD) in a prospective two-year follow-up dual-energy X-ray absorptiometry (DEXA) study.

Methods

After power analysis, a consecutive series of 25 patients with unilateral Bicontact® stem implantation was examined clinically and underwent DEXA examinations. Scans of seven regions of interest were taken preoperatively and at one week, six months, and one and two years.

Results

One patient required stem revision due to a deep infection. The Harris Hip Score increased significantly by 44 points. The most significant bone loss was observed in the calcar region (R7) in the first six months (−19.2 %). It recovered in the following 18 months to −8.5 %. The BMD in the greater trochanter dropped significantly after six months and remained stable at this level. BMD exceeded baseline values in distal regions and even more in the lesser trochanter region after two years.

Conclusions

We conclude that the Bicontact® stem provides adequate proximal bone stock preservation. We observed some signs of stress shielding at the tip of the stem, which is inevitable to some degree in THA with cementless straight stems. However, in this prospective DEXA investigation, we showed that proximal off-loading does not occur after THA with the Bicontact® system. Thus, we believe that this stem is still a state-of-the-art implant.     

Psychosocial outcomes among youth with spinal cord injury by neurological impairment

Objective

Examine psychosocial outcomes of youth with spinal cord injury (SCI) as a function of neurological level (paraplegia/tetraplegia) and severity (American Spinal Injury Association (ASIA) Impairment Scale (AIS)).

Design

Survey research.

Setting

Three pediatric SCI specialty centers in the USA.

Participants

Youth with SCI ages 5–18 with neurological impairment classifications of: tetraplegia AIS ABC (tetraplegia ABC), paraplegia AIS ABC (paraplegia ABC), or AIS D.

Outcome Measures

Children''s Assessment of Participation and Enjoyment, Pediatric Quality of Life Inventory, Revised Children''s Manifest Anxiety Scale, and Children''s Depression Inventory.

Results

Three hundred and forty youth participated; 57% were male; 60% were Caucasian, 21% Hispanic, 7% African-American, 2% Native American, and 3% reported “other”. Their mean age was 8.15 years (standard deviation (SD) = 5.84) at injury and 13.18 years (SD = 3.87) at interview. Ninety-six youth (28%) had tetraplegia ABC injuries, 191 (56%) paraplegia ABC injuries, and 53 (16%) AIS D injuries. Neurological impairment was significantly related to participation and quality of life (QOL). Specifically, youth with paraplegia ABC and AIS D injuries participated in more activities than youth with tetraplegia ABC (P = 0.002; P = 0.018, respectively) and youth with paraplegia ABC participated more often than youth with tetraplegia ABC (P = 0.006). Youth with paraplegia ABC reported higher social QOL than youth with tetraplegia ABC (P = 0.001) and AIS D injuries (P = 0.002). Groups did not differ regarding mental health.

Conclusion

Interventions should target youth with tetraplegia ABC, as they may need support in terms of participation, and both youth with tetraplegia ABC and AIS D injuries in terms of social integration.     

An Association Can Be Found Between Hounsfield Units and Success of Lumbar Spine Fusion

Background

Measuring Hounsfield units (HUs) from computed tomography (CT) scans has recently been proposed as a tool for assessing vertebral bone quality, as it has been associated with bone mineral density, compressive strength, and fracture risk. Vertebral bone quality is believed to be an important determinant of outcome and complication rates following spine surgery and potentially influences success of interbody spinal fusion.

Questions/Purposes

The purpose of this study was to investigate the association between HU on CT scans and fusion success in patients with lateral transpsoas surgery for lumbar interbody fusion (LIF).

Methods

The CT scans of 28 patients with a combined 52 levels of stand-alone LIF were evaluated at a minimum of 12 weeks postoperatively. Coronal and sagittal images were evaluated for evidence of fusion, and HU values were collected from axial images. HU measurements were also taken from vertebral bodies proximal to the construct to evaluate global bone quality.

Results

Of the 52 LIF levels, 73% were assessed as fused and 27% were nonunited at the time of evaluation. The successful fusion levels had significantly higher HU measurements than the nonunion levels (203.3 vs. 139.8, p < 0.001). Patients with successful fusion constructs also had higher global bone density when vertebral bodies proximal to the construct were compared (133.7 vs. 107.3, p < 0.05).

Conclusion

With the aging population and increasing prevalence of osteoporosis, preoperative assessment of bone quality prior to spinal fusion deserves special consideration. We found that a successful lumbar fusion was associated with patients with higher bone density, as assessed with HU, both globally and within the fusion construct, as compared to patients with CT evidence of nonunion.

Electronic supplementary material

The online version of this article (doi:10.1007/s11420-013-9367-3) contains supplementary material, which is available to authorized users.     

Stress fractures in elderly patients

Purpose

The purpose of this study was to investigate specific risk factors, common fracture locations and possible sex-specific differences in elderly patients with stress fractures.

Methods

This analysis enrolled 105 patients (83 women, 22 men) with stress fractures. For the analysis of possible risk factors related to increasing age, data from 82 patients (67 women, 15 men) aged 40 years and older (mean age of 57.4 ± 11.0 years) were compared with that from a younger control group [23 patients (16 women, seven men), mean age 28.4 ± 6.7 years]. Bone mineral density (BMD) was determined using dual-energy X-ray absorptiometry bone densitometry (DXA) and blood samples were taken.

Results

A total of 211 stress fractures were found. Of these, 177 were found in the study group, of which 90.4 % were located in the lower limb. Lumbar and femoral BMD was significantly lower in elderly patients; however, the BMD of most patients was within the osteopenic or normal range. Within the study group, a total of 83.8 % had a vitamin D insufficiency (<30 μg/l); 75.5 % were not engaged in regular physical activity more than once a week. Overweight patients within the study group had significantly more stress fractures compared to normal weight patients (2.6 ± 1.7 vs. 1.9 ± 1.1, p<0.05).

Conclusions

A similar contribution of risk factors has been found for stress fractures in elderly patients and younger controls of the general population. Stress fracture incidence seems to be rather multifactorial and not based on osteoporotic changes alone. A balanced calcium and vitamin D metabolism seems to be of paramount importance for stress fracture prevention in elderly patients.