Full-thickness tendon tears of the supraspinatus (SP) are common and can have a significant impact on shoulder function. To optimally treat supraspinatus tendon tears an accurate understanding of its musculotendinous architecture is needed. We have previously shown that the architecture of supraspinatus is complex. It has architecturally distinct regions: anterior and posterior, each of which is further subdivided into superficial, middle and deep parts (Kim et al., 2007). Data of FBL and PA of the torn supraspinatus could enhance clinical decision making and guide rehabilitative treatments (Ward et al., 2006). Currently, however, in vivo US quantification of the fiber bundle architecture of the distinct regions of supraspinatus in subjects with full-thickness tendon tears has not been investigated. PURPOSE: To quantify architectural parameters within the distinct regions of supraspinatus in subjects with a full-thickness tendon tear using the US protocol that we previously developed (Kim et al., 2010), and to compare findings with age and gender matched normal controls. Twelve SP from eight subjects, mean age 576.0 years, were scanned using an US scanner (12 MHz). The SP was scanned in relaxed and contracted states. For the contracted state, SP was scanned with the shoulder in neutral rotation and 60 of active abduction. Fiber bundles of the anterior region (middle and deep) and posterior region (deep) could be visualized and measured. Muscle thickness, FBL, and PA were computed from US scans. Data was analyzed using Mann-Whitney and Wilcoxon Signed Rank Tests (P<0.05).Purpose
Method
Rotator cuff tears are common injuries which often require surgical repair. Unfortunately, repairs often fail [1] and improved repair strength is essential. P2 Porous titanium (DJO Surgical, Austin TX) has been shown to promote osseointegration [2,3] and subdermal integration [4]. However, the ability of P2Porous titanium to aid in supraspinatus tendon-to-bone repair has not been evaluated. Therefore, the purpose of this study was to investigate P2 implants used to augment supraspinatus tendon-to-bone repair in a rat model [5]. We hypothesized that supraspinatus tendon-to-bone repairs with P2 implants would allow for ingrowth and increased repair strength when compared to standard repair alone. Thirty-four adult male Sprague-Dawley rats were used (IACUC approved). Rats received bilateral supraspinatus detachment and repair with one limb receiving P2 implant. Animals were sacrificed at time 0 (n=3), 2 weeks (n=8), 4 weeks (n=9) and 12 weeks (n=14). Limbs were either dissected for histological and SEM analysis or mechanical testing as described previously [5]. Specimens for histology and SEM were embedded in PMMA for tissue-implant interface analysis. Specimens were first viewed in SEM under BSE to detect bony ingrowth, then stained with Sanderson's Rapid Bone Stain and viewed under transmitted and polarized light for tissue ingrowth. Comparisons were made using Student's t-tests with significance at p≤0.05.INTRODUCTION
METHODS
To assess the long term MRI pathoanatomical changes of unrepaired, isolated full thickness supraspinatus tears in a population of patients that had acromioplasty done for symptomatic impingement syndrome. To date there are no studies assessing the effect of acromioplasty on rotator cuff tear progression in impingement syndrome. The natural evolution of unrepaired tears suggests that small isolated tears may heal, and not all tears progress onto significant fatty change and atrophy. Which tears heal and which tears progress and the effect of acromioplasty on tear progression is still not known.Aim:
Background:
Introduction. Shoulder arthoplasty has increased in the last years and its main goal is to relieve pain and restore function. Shoulder prosthesis enters in the market without any type of pre-clinical tests. Within this paper we present study experimental and computational tests as pre-clinical testing to evaluate total shoulder arthoplasty performance. Materials and methods. An in vitro experimental simulator was designed to characterize experimentally the intact and implanted shoulder glenoid articulation. Fourth generation Sawbones® composite left humerus and scapula were used and the cartilage was replicated with silicone for the intact articulation (figure 1). In the intact experimental articulation we considered the inferior glenohumeral ligament as an elastic band with equivalent mechanical properties. For the implanted shoulder, the Comprehensive® Total Shoulder System (Biomet®) with a modular Hybrid® glenoid base and Regenerex® central post was considered (figure 2). The prostheses were implanted by an experienced surgeon and clinical results from orthopedic registers were collected. The system structures were placed to simulate 90º in abduction, including the following muscle forces: Deltoideus 300N, Infraspinatus 120N,
