Purpose of this study is to create an experimental model of electrophysologic evaluation of the supraspinatus muscle on rats, after traumatic rupture of its tendon. The population of this study consisted of 10 male Sprague Dawley rats weighting 300–400g. Under general anaesthesia we proceeded with traumatic rupture of the supraspinatus tendon and exposure of the muscle. The scapula was immobilized, and the supraspinatus tendon was attached to a force transducer using a 3–0 silk thread. A dissection was performed in order to identify the suprascapular nerve, which was then stimulated with a silver electrode. Stimulations were produced by a stimulator (Digitimer Stimulator DS9A) and were controlled by a programmer (Digitimer D4030). Fiber length was adjusted until a single stimulus pulse elicited maximum force during a twitch under isometric conditions. Rectangular pulses of 0.5 ms duration were applied to elicit twitch contractions. During the recordings, muscles were rinsed with Krebs solution of approximately 37 8C (pH 7.2–7.4) and aerated with a mixture of 95% O2 and 5% CO2. The output from the transducer was amplified and recorded on a digital interface (CED). The following parameters were measured at room temperature (20–21 8C): single twitch tension; time to peak; half relaxation time; tetanic tensions at 10, 20, 40, 80 and 100 Hz; and fatigue index, which was evaluated using a protocol of low frequency (40 Hz) tetanic contraction, during 250 ms in a cycle of 1 s, for a total time of 180 s. The fatigue index value was then calculated by the formula [fatigue index=(initial tetanic tension − end tetanic tension) ∗ 100/(initial tetanic tension)]. In the end, the transducer was calibrated with standard weights and tensions were converted to grams. The mean single twitch was 8.2, the time to peak 0.034 msec and the half relaxation time 0.028 msec. The strength of titanic
This is a prospective randomised study which compares the radiological
and functional outcomes of ring and rail fixators in patients with
an infected gap (>
3 cm) nonunion of the tibia. Between May 2008 and February 2013, 70 patients were treated
at our Institute for a posttraumatic osseocutaneous defect of the
tibia measuring at least 3 cm. These were randomised into two groups
of 35 patients using the lottery method. Group I patients were treated
with a ring fixator and group II patients with a rail fixator. The
mean age was 33.2 years (18 to 64) in group I and 29.3 years (18
to 65) in group II. The mean bone gap was 5.84 cm in group I and 5.78
cm in group II. The mean followup was 33.8 months in group I and 32.6 months
in group II. Bone and functional results were assessed using the
classification of the Association for the Study and Application
of the Method of Ilizarov (ASAMI). Functional results were also
assessed at six months using the short musculoskeletal functional
assessment (SMFA) score.Aims
Patients and Methods