Does additional patella tendon shortening influence the effects of multilevel surgery to correct flexed knee gait in cerebral palsy: A randomized controlled trial.

BACKGROUND: The aims of this study were to investigate if patellar tendon shortening (PTS) as a part of SEMLS (single event multilevel surgery) is effective for reduction of flexed knee gait in children with cerebral palsy (CP) and, if PTS leads to stiff knee gait. METHODS: In a randomized controlled study 22 children with flexed knee gait (age: 10.4 ±â€¯2.6 years, GMFCS Level I-III) were randomized and allocated to two groups (1: SEMLS + PTS; 2: SEMLS no PTS): SEMLS was performed for correction of flexed knee gait either with or without additional PTS. Before and after surgery (follow up: 12.7 ±â€¯1.6 months) kinematics (3-D motion analysis) and clinical parameters were compared. RESULTS: Two children were lost to follow up. Maximum knee extension improved significantly in both groups after SEMLS while the patients with additional PTS showed much more correction (SEMLS + PTS: 37.6° to 11.4°, p = 0.007; SEMLS no PTS: 35.1° to 21.8°, p = 0.016). After surgery peak knee flexion decreased significantly (14.6°, p = 0.004) in the "SEMLS + PTS" group while there was no relevant change in the other group. There was a trend of increase in anterior pelvic tilt after surgery in both groups, but no statistical significant difference. After surgery knee flexion contracture (15.9°, p < 0.001) and popliteal angle (27.2, p = 0.009) measured on clinical examination only decreased significantly in the "SEMLS + PTS" group. CONCLUSION: PTS is effective for correction of flexed knee gait and knee flexion contracture leading to superior stance phase knee extension. However, additional PTS may lead to stiff knee gait and a higher increase of anterior pelvic tilt.

Can reverse shoulder arthroplasty in post-traumatic revision surgery restore the ability to perform activities of daily living?

BACKGROUND: Failed shoulder arthroplasty and failed internal fixation in fractures of the proximal humerus can benefit from implantation of a reverse total shoulder arthroplasty (RSA). While there is some evidence that RSA can improve function regarding range of motion (ROM), pain, satisfaction, and strength, there is sparse data how this translates into activities of daily living (ADLs). A marker-based 3D video motion analysis system has recently been designed that can measure changes of ROM in dynamic movements in every plane. The hypothesis was that a gain of maximum ROM also translates into the ability to perform ADLs and into a significant increase of ROM in ADLs. MATERIALS AND METHODS: Six consecutive patients (5 women, 1 man; 2× failed arthroplasty, 4× failed open reduction and internal fixation) who received RSA were examined the day before and 1 year after shoulder replacement. A 3D motion analysis system using a novel upper extremity model measured active maximum values and ROM in four ADLs. RESULTS: Comparing the pre- to the 1-year postoperative status, RSA resulted in a significant increase in mean maximum values for active flexion (humerus to thorax) of 37° (S.D. ±23°), from 50 to 87° [P=0.005], and for active abduction averaging of 17° (S.D. ±13°), from 52 to 69° [P=0.027]. The extension decreased significantly by about 8° (S.D. ±16°), from a mean of 39 to 31° [P=0.009]. For active adduction and internal and external rotation, there were trends for improvements, but no significant changes. Only three additional tasks of the ADL (out of 13/24 preoperatively) could be performed after revision surgery. Comparing the preoperative to the postoperative ROM in the ADLs in flexion/extension, ROM improved significantly in one ("tying an apron") of four ADLs. There were no significant changes in the abduction/adduction and internal/external rotation in any ADLs. CONCLUSION: RSA in revision cases significantly improved maximum active flexion and abduction, but decreased extension in this series. However, the patients were only able to use this greater ROM to their benefit in one of four ADLs.

The effects of muscle-tendon surgery on dynamic electromyographic patterns and muscle tone in children with cerebral palsy.

During multilevel surgery, muscle-tendon lengthening (MTL) is commonly carried out in children with cerebral palsy. However, it is unclear if MTL also modifies increased muscle tone and if pathologic activation patterns are changed as an indirect effect of the biomechanical changes. Since investigations addressing this issue are limited, this study aimed at evaluating the effects of MTL on muscle tone and activation pattern. Forty-two children with spastic diplegia who were treated by MTL underwent standardized muscle tone testing (modified Ashworth and Tardieu test), dynamic EMG and three-dimensional gait analysis before, one and three years after MTL. For the evaluation of muscle activation patterns the norm-distance of dynamic EMG data was analyzed. Range of motion and joint alignment in clinical examination were found to be significantly improved one year after MTL. However, deterioration of these parameters was noted after three years. Muscle tone was significantly reduced one year postoperatively but showed an increase after three years. Joint kinematics were found significantly closer to reference data of age matched controls initially after surgery, but deteriorated until three years postoperatively. However, the EMG patterns of the muscles which were surgically addressed were found to be unchanged in either follow-up. These findings suggest that despite the influence of MTS on biomechanics and physiology (muscle tone reduction and improvements of joint mobility and gait pattern) MTS does not change abnormal patterns of muscle activation. Recurrence of increased muscle tone and deterioration of kinematic parameters three years after surgery may be attributed to these persistent pathologic activation patterns.

Transform coding of stereo image residuals.

Stereo image compression is of growing interest because of new display technologies and the needs of telepresence systems. Compared to monoscopic image compression, stereo image compression has received much less attention. A variety of algorithms have appeared in the literature that make use of the cross-view redundancy in the stereo pair. Many of these use the framework of disparity-compensated residual coding, but concentrate on the disparity compensation process rather than the post compensation coding process. This paper studies specialized coding methods for the residual image produced by disparity compensation. The algorithms make use of theoretically expected and experimentally observed characteristics of the disparity-compensated stereo residual to select transforms and quantization methods. Performance is evaluated on mean squared error (MSE) and a stereo-unique metric based on image registration. Exploiting the directional characteristics in a discrete cosine transform (DCT) framework provides its best performance below 0.75 b/pixel for 8-b gray-scale imagery and below 2 b/pixel for 24-b color imagery, In the wavelet algorithm, roughly a 50% reduction in bit rate is possible by encoding only the vertical channel, where much of the stereo information is contained. The proposed algorithms do not incur substantial computational burden beyond that needed for any disparity-compensated residual algorithm.