Hans-Joachim Riesner

Effects of knee bracing on postural control after anterior cruciate ligament rupture

STUDY DESIGN Randomized clinical trial. OBJECTIVES To investigate the effects of functional knee braces on postural control in patients with anterior cruciate ligament (ACL) rupture. BACKGROUND ACL rupture leads to both mechanical knee instability and deficits in proprioception. Although elastic knee braces do not increase mechanical stability, patients report improved stability when wearing a brace. Elastic braces were found to reduce the loss of proprioception. It is, however, still unclear whether they also improve postural control, which involves the processing of proprioceptive input at a higher level. METHODS We studied 58 patients with isolated unilateral ACL rupture using computerized dynamic posturography and compared overall stability index (OSI) scores for injured and uninjured legs with and without a knee brace. In addition, patients were classified as copers and non-copers depending on knee function. RESULTS Within subjects, OSI scores were 3.0 ± 1.1° for uninjured legs when unbraced, 2.8±1.3° for uninjured legs when braced (p=0.17), 3.7 ± 1.5° for unbraced injured legs, and 2.9 ± 1.3° for braced injured legs (p<0.001). For the injured legs of copers and non-copers, OSI scores were 3.4° ± 1.2° for copers and 4.0° ± 1.6° for non-copers in the unbraced condition (p=0.11) and 2.7 ± 1.0° for copers and 3.1 ± 1.4° for non-copers in the braced condition (p=0.26). CONCLUSION Elastic knee braces increase postural stability by approximately 22% in patients with ACL rupture. There was no difference in postural stability between uninjured and injured legs in the braced condition. One possible explanation is that bracing improves both proprioception and postural control.

Computerized dynamic posturography: the influence of platform stability on postural control.

ObjectivePostural stability can be quantified using posturography systems, which allow different foot platform stability settings to be selected. It is unclear, however, how platform stability and postural control are mathematically correlated. DesignTwenty subjects performed tests on the Biodex Stability System at all 13 stability levels. Overall stability index, medial-lateral stability index, and anterior-posterior stability index scores were calculated, and data were analyzed using analysis of variance and linear regression analysis. ResultsA decrease in platform stability from the static level to the second least stable level was associated with a linear decrease in postural control. The overall stability index scores were 1.5 ± 0.8 degrees (static), 2.2 ± 0.9 degrees (level 8), and 3.6 ± 1.7 degrees (level 2). The slope of the regression lines was 0.17 for the men and 0.10 for the women. ConclusionsA linear correlation was demonstrated between platform stability and postural control. The influence of stability levels seems to be almost twice as high in men as in women.

Dual Energy Computed Tomography in Musculoskeletal Imaging, with Focus on Fragility Fractures of the Pelvis

Dual energy computed tomography (DECT) is a constantly evolving technology, which opens up new diagnostic possibilities. It is particularly valuable for musculoskeletal (MSK) imaging. Due to the lack of recognition and availability of dual energy scanners, routine use is only established in a few centres. The intention of this review is to show the possibilities and fields of applications of the DECT in MSK imaging, as well as to describe technical principles and typical indications. We mainly focus on the use of DECT in the context of fragility fractures of the pelvis. The use of the DECT in pelvic fractures of the elderly could combine the advantages of CT diagnostics - fast and continuous availability, lower costs by dispensing with a supplementary MRI examination - and the high sensitivity of MRI to oedema in fragility fractures. Furthermore, the latest DECT scanners are dose neutral, so that these examinations can also be carried out without increased radiation exposure.

Biomechanical in vitro comparison of radiofrequency kyphoplasty and balloon kyphoplasty

PurposeBalloon kyphoplasty (BK) has emerged as a popular method for treating osteoporosis vertebral compression fractures (OVCFs). In response to several shortcomings of BK, alternative methods have been introduced, among which is radiofrequency kyphoplasty (RFK). Biomechanical comparisons of BK and RFK are very sparse. The purpose of this study was to perform a biomechanical study in which BK and RFK are compared.MethodsEach of the two study groups comprised six specimens prepared from two functional spinal units (FSUs) cut from fresh-frozen cadaveric spines (3 of T9–T11 and 3 of T12–L2). VCFs (A1.2 type) were created in the middle VB of each of the FSUs, with a height loss of 30% of the VB. After that, the specimens were subjected to cyclic compression–compression loading. The following parameters were determined: range of motion (ROM), height of the middle VB, augmentation time, cement interdigitation and cement distribution. Also, the cement layer, the trabecular bone in the augmented VB and the bone–cement interface were examined for cracks. All of these parameters were determined at various stages, namely in the intact middle VB and after its fracture, cement augmentation and subject to the cyclic loading protocol.ResultsFractures caused a significant increase in median ROM and a significant reduction in the height of fractured VB. Cement augmentation significantly stabilized the fractures and led to partial height restoration. ROM and vertebral height, however, were not restored to the intact levels. Cyclic loading led to a further significant increase in ROM and a significant height reduction. There were no significant differences between BK and RFK in terms of any of these parameters.ConclusionsBK and RFK achieved similar results for fracture stabilization and restoration of the height of the fractured VB. RFK involved shorter cement augmentation time and less damage to the trabecular bone.

Influence of Submaximal Exercise on Postural Control in Older Adults.

ObjectiveThe authors conducted this cross-sectional study to assess the influence of submaximal exercise on postural stability as measured by computerized dynamic posturography (CDP) and compared this study’s CDP results with clinical balance tests such as the Berg Balance Test and the Timed Up and Go test using a descriptive/explorative approach. DesignForty-three participants performed two exercise tasks (6-min walk test and stair climbing). CDP and established scores (Berg Balance Test and Timed Up and Go test) were used to assess postural instability. ResultsDespite significant pulse rate increases (approximately 20%, P < 0.05), no clear differences in CDP results were found after completion of either exercise task. The overall stability index scores for all subjects remained unchanged (P = 0.98). A descriptive analysis showed that excellent Berg Balance Test and Timed Up and Go test results were associated with good CDP results. ConclusionsSubmaximal exercise did not adversely affect postural stability in these older adults. To Claim CME Credits:Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME Objectives:After completion of this article, readers should be able to: (1) Appreciate the impact of falls on the health of the elderly; (2) Understand afferent input contributing to postural control; and (3) Appreciate the effects of submaximal exercise on postural stability in the elderly. Level:Advanced Accreditation:The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The Association of Academic Physiatrists designates this activity for a maximum of 1.5 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Dynamic Posterior Stabilization versus Posterior Lumbar Intervertebral Fusion: A Matched Cohort Study Based on the Spine Tango Registry

Purpose The primary aim of dynamic stabilization is to stabilize the spine and preserve function without overstressing adjacent segments, which is a potential risk of fusion surgery. However, direct comparative analyses of the two approaches are still limited, and little is known about the association of patient‐reported outcomes with these treatment options. Objective To compare the clinical outcomes of dynamic posterior stabilization using the DSS Stabilization System (Paradigm Spine, LLC, New York, New York, United States) versus posterior lumbar intervertebral fusion (PLIF) based on data from a spine registry. We hypothesized that patient‐reported outcomes of DSS are not inferior to those of PLIF. Methods We identified 202 DSS and 269 PLIF patients with lumbar degenerative disease with a minimum 2‐year follow‐up. A 1:1 propensity score‐based matching was applied to balance the groups for various patient characteristics. The primary outcome was the change in the patient‐reported Core Outcome Measures Index (COMI; a 0‐10 scale) score. Results The matching resulted in 77 DSS‐PLIF pairs (mean age: 67 years; average COMI follow‐up: 3.3 years) without residual significant differences in baseline characteristics. The groups showed no difference in improved COMI score (p = 0.69), as well as in back (p = 0.51) and leg pain relief (p = 0.56), blood loss (p = 0.12), and complications (p > 0.15). Fewer repeat surgeries occurred after DSS (p = 0.01). The number of repeat surgeries per 100 observed person‐years was 0.8 and 2.9 in DSS and in PLIF patients, respectively. Furthermore, shorter surgery time (p < 0.001) and longer hospital stays (p = 0.03) were observed for DSS cases. Conclusion In a midterm perspective, DSS may be a viable alternative to PLIF because both therapies result in similar COMI score improvement. Advantages of DSS may be shorter duration of surgery and fewer repeat surgeries. However, more than half of DSS patients did not find a match with a PLIF patient, suggesting that the patient profiles may be different. Further multicenter studies are needed to better understand the most appropriate indication for each therapy.

Diagnostic Accuracy of Fluoroscopy, Radiography, and Computed Tomography in Detecting Cement Leakage in Kyphoplasty

Purpose Cement leakage is a typical complication of kyphoplasty for vertebral fractures. It is unclear if cement application intraoperatively can be improved by using other techniques of visualization and which kind of postoperative imaging should be recommended to detect cement extravasation accurately. Objective To compare the rates of cement leakage detected by intraoperative fluoroscopy, postoperative radiography, and postoperative computed tomography (CT) in a retrospective study. Patients and Methods The study included 78 patients (60 women and 18 men; 115 vertebral bodies) who were treated with two kinds of kyphoplasty. The patients underwent intraoperative fluoroscopy and postoperative radiography and CT. After surgery, the images were evaluated to compare cement leakage rates and locations in the three visualization techniques. Leakage locations were described as epidural, intradiskal, extravertebral, or intravascular. Results Compared with CT, intraoperative fluoroscopy regularly detected intradiskal leakage (75%) but had a considerably lower sensitivity for visualizing epidural (21%), extravertebral (31%), and intravascular (51%) cement leakages. A comparison of radiography and CT showed that radiography had a high sensitivity for detecting intradiskal (82%) and intravascular (70%) cement extrusions but a lower sensitivity in identifying epidural (42%) and extravertebral (50%) leaks. Therefore, the CT scan overall was best in detecting location and accuracy. Conclusion CT detected more cement leaks than any of the other investigated techniques, especially epidural, extravertebral, and intravascular cement leakages. To achieve the best accuracy, only CT provides complete information.