Introduction

Differing levels of tendon retraction are found in full-thickness rotator cuff tears. The pathophysiology of tendon degeneration and retraction is unclear. Neoangiogenesis in tendon parenchyma indicates degeneration. Hypoxia inducible factor 1(HIF) and vascular endothelial growth factor (VEGF) are important inducers of neoangiogenesis. Rotator cuff tendons rupture leads to fatty muscle infiltration (FI) and muscle atrophy (MA). The aim of this study is to clarify the relationship between HIF and VEGF expression, neoangiogenesis, FI, and MA in tendon retraction found in full-thickness rotator cuff tears.

Introduction: Goal of study to demonstrate that treatment with low-intensity pulsed ultrasound [LIPUS] results in greater increases in bone density and greater reductions in bone gap area as compared to sham control in tibia fractures with delayed union (no progression of healing for at least four months).

Methods: Two primary effectiveness variables, change of bone density and gap area during treatment, were selected as surrogates for bone healing. Abbreviated treatment period was maximum that sham treatment could be administered ethically. Both variables measured by blinded central reviewers from CT-scans taken before/after termination of treatment. All adverse events recorded, evaluated. Treatment duration was 16wks. Patients instructed to apply device once daily for 20 minutes. Control devices were visually identical but did not transmit ultrasound waves. Neither patients nor physicians could recognize shams.

Results: 101 patients enrolled (51 LIPUS, 50 sham), mean age 42.6 (active) versus 45.1 years (sham). Based on log-transformed data, mean improvement in bone density was 1.34 (90% CI 1.14 to 1.57) times greater for patients randomized to LIPUS compared to sham (p=0.002). A mean reduction in bone gap area also favored LIPUS treatment (p=0.014).

Conclusion: Double-blind, intent-to-treat analyses demonstrated statistically significant superior effectiveness for LIPUS device compared to sham in terms of both endpoints over 16wks of treatment. Estimated increase in bone density among patients randomized to LIPUS treatment was 34% greater than among patients randomized to sham. A significantly greater mean reduction in bone gap area after LIPUS treatment was also shown. Evaluation of adverse events showed that ultrasound therapy is safe.

Aim: The assessment of shoulder mobility is essential for clinical follow-up of shoulder treatment. Only a few high sophisticated instruments for objective measurements of shoulder mobility are available. The interobserver dependency of conventional goniometer measurements is high. In the 1990s an isokinetic measuring system of BIODEX Inc. was introduced, which is a very complex but valid instrument. Since 2008 a new user-friendly system (DynaPort ShoulderTest-System) is available. Aim of this study is the validation of this measuring instrument with the BIODEX-System.

Methods: The DynaPort ShoulderTest-System is a small, light-weighted three-dimensional gyroscope that is fixed on the distal upper patient arm, recording abduction, fiexion and rotation. For direct comparison we fixed the DynaPort on the lever arm of the BIODEX-system. The accuracy of measurement was determined at different positions, angles and distances from the center of rotation as well as different motion speeds in the radius between 0° – 180° in steps of 20°. All measurements were repeated ten times and observed with a digital water level. As satisfactory accuracy we defined a difference between both systems below 5°. The statistical analysis was performed with a linear regression model.

Results: The evaluation showed very high accuracy of measurements. The maximum average deviation was 0,5°. Below 60° the DynaPort was underestimating comparing the BIODEX system, whereas in higher positions higher data was measured. At higher angles the differences between both got higher. The distance to the center of rotation as well as the position of the Dyna-Port on the lever arm and different motion speeds infiuenced the results. The highest significant matches were measured at highest distance from the center of rotation (1,8° vs. 3,1°, p < 0,05) and a highest motion speed (2,1° at 60°/s, vs. 3,1° at 30°/s, p < 0,05).

Conclusion: In summary the results showed a high correlation and good reproducibility of measurements. All deviations were inside the tolerance interval of 5 °. These laboratory trials are promising for the validation of this system in shoulder patients. The challenge for both systems will be the changing of the center of rotation in the shoulder joint at elevations higher than 90°.