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Biomedical subjects

Daniel A Rikli

Publications and source records attributed to Daniel A Rikli.

4 recordsLinked to original sources
PubMed2007

Intra-articular pressure measurement in the radioulnocarpal joint using a novel sensor: in vitro and in vivo results.

PURPOSE: To determine the amount and distribution of forces transmitted across the human radioulnocarpal joint under physiologic conditions in vivo. We performed an in vitro validation of a specifically developed capacitive pressure-sensor device and an in vivo measurement of force transmission and pressure distribution at the radioulnocarpal joint in a healthy volunteer. METHODS: A new capacitive pressure-sensor device was adapted for intra-articular pressure measurement in the human radioulnocarpal joint. The technical characteristics of the device were determined and the sensor was validated in fresh-frozen cadaver tests. Force transmission across the radioulnocarpal joint then was measured in healthy volunteers under local anesthesia. RESULTS: The sensor delivered reproducible measurements of forces across the radioulnocarpal joint and their distribution in the cadaver experiment. In vivo, 2 centers of force transmission were identified. None of these centers correlated with previous findings in the literature. More force is transmitted across the ulnar side of the radioulnocarpal joint than previously thought. The results are consistent with clinical findings. CONCLUSIONS: The novel sensor device is suitable for intra-articular pressure measurement in the human radioulnocarpal joint in vitro and in vivo.

Biomechanical Phenomena↗
PubMed2005

Dorsal double-plate fixation of the distal radius.

OBJECTIVE: Restoration of the intra- and extraarticular anatomy of the distal radius. Stable internal fixation of fragments, with the possibility of early functional rehabilitation. INDICATIONS: Distal intraarticular radius fractures with impacted articular fragments and displaced dorsoulnar fragment. Distal intraarticular radius fractures with bony or ligamentous injury of the proximal carpal row. CONTRAINDICATIONS: General medical contraindications for surgical intervention. Distal radius fractures with palmar tilt of the distal fragment. SURGICAL TECHNIQUE: Dorsal longitudinal incision. Approach to the intermediate column via the third extensor compartment by detaching the extensor pollicis longus (EPL) tendon. Arthrotomy and revision of the proximal carpal row. Reconstruction of the radiocarpal articular surface and support with a plate applied to the dorsoulnar aspect. Approach to the radial column by subcutaneous preparation between skin flaps (cave: superficial branch of the radial nerve) and retinaculum, incision of the first extensor compartment and support of the radial column with a preshaped plate, which is pushed through under the tendons of the first compartment. Cancellous bone grafting is usually not necessary. Subcutaneous displacement of the EPL tendon with the aid of a small retinacular flap. MANAGEMENT RESULTS: Application of a removable velcro cuff. Immediate functional postoperative physiotherapy, without the cuff. No straining or forcing until first radiographic examination at 6 weeks after the operation. RESULTS: 25 consecutive patients were monitored following a double-plate fixation, with a minimum follow-up of 12 months. In all cases the reduction, in accordance with the Stewart Score, was very good, a loss of reduction was not observed. The range of motion was between 100 degrees and 160 degrees for flexion/extension and between 160 degrees und 180 degrees for pronation/supination. The average DASH Score was 7.2 points, the PRWE Score 8.0 points. No relevant loss of strength (JAMAR dynamometer) was found in any of the patients in comparison with the healthy side. Complications noted were a muscle adhesion in the region of the first extensor compartment as well as a mild reflex sympathetic dystrophy, which healed without consequences. Implants were removed from six of the patients.

Adolescent↗