In vivo assessment of time dependent changes of T2* in medial meniscus under loading at 3T: A preliminary study.

Due to the internal structure of the knee joint, the ability to characterize and quantify the dynamic response of the meniscal tissue directly in vivo is highly problematic. The main purpose of this study was to investigate the behaviour of the meniscus under loading conditions. Four healthy young females were included. To obtain T2* values in the meniscus, the vTE sequence was used with 10 echoes ranging from 0.8 to 10.1 ms. Submilisecond first echo time is a great advantage of vTE sequence allowing for precise mapping of relatively short T2*. The two-parametric least squares fitting procedure was used to calculate T2* pixel-wise. A custom-made diamagnetic apparatus was developed to simulate stress conditions on the lower limb in a conventional MR scanner. vTE T2* was performed in five consecutive scans, 6:10 min apart. Three different compartments of the medial and lateral meniscus were segmented. The differences at the different time-points were calculated. A constant increase of T2* times after compression was statistically significant in the anterior horn of the medial meniscus. T2* mapping with variable echo time sequence might be a satisfactorily sensitive technique to detect the changes of meniscus physiology under loading conditions in vivo.

Possibilities of objective identification of meniscoids in joint blocks of the axial system, by MRI and Transfer Vibration through the Spine.

OBJECTIVE: The aim of the study was to identify the meniscoids of the cervical spine using in-vivo MRI imaging and to determine their potential role in the development of functional joint blocks of the axial system (AS). Another objective was to find out how the articular blocks affect the rheological properties of the spine by the Transfer Vibration through the Spine (TVS) method. METHOD: In this study were used methods TVS and MRI. The study was conducted on a research file of 12 subjects and was conceived as a pilot one. RESULTS: It has been shown that the MRI method, in appropriate circumstances, enables the detection of changes in the size and shape of meniscoids in-vivo. On the basis of the investigations carried out, it can be assumed that several mechanisms are involved in the formation of functional joint blocks, and are not primarily caused by the incarceration of meniscoidal tissue. Using the TVS method, it has also been found that a functional articular blockade affects the rheological properties of the axial system, specifically reducing the damping capabilities of the particular spine segment. CONCLUSION: In the follow-up studies, it will be necessary to verify the theoretical interpretations on a larger statistical set.

Isolated talonavicular arthrodesis in patients with rheumatoid arthritis of the foot and tibialis posterior tendon dysfunction.

BACKGROUND: The foot is often affected in patients with rheumatoid arthritis. Subtalar joints are involved more frequently than ankle joints. Deformities of subtalar joints often lead to painful flatfoot and valgus deformity of the heel. Major contributors to the early development of foot deformities include talonavicular joint destruction and tibialis posterior tendon dysfunction, mainly due to its rupture. METHODS: Between 2002 and 2005 we performed isolated talonavicular arthrodesis in 26 patients; twenty women and six men. Tibialis posterior tendon dysfunction was diagnosed preoperatively by physical examination and by MRI. Talonavicular fusion was achieved via screws in eight patients, memory staples in twelve patients and a combination of screws and memory staples in six cases. The average duration of immobilization after the surgery was four weeks, followed by rehabilitation. Full weight bearing was allowed two to three months after surgery. RESULTS: The mean age of the group at the time of the surgery was 43.6 years. MRI examination revealed a torn tendon in nine cases with no significant destruction of the talonavicular joint seen on X-rays. Mean of postoperative followup was 4.5 years (3 to 7 years). The mean of AOFAS Hindfoot score improved from 48.2 preoperatively to 88.6 points at the last postoperative followup. Eighteen patients had excellent results (none, mild occasional pain), six patients had moderate pain of the foot and two patients had severe pain in evaluation with the score. Complications included superficial wound infections in two patients and a nonunion developed in one case. CONCLUSIONS: Early isolated talonavicular arthrodesis provides excellent pain relief and prevents further progression of the foot deformities in patients with rheumatoid arthritis and tibialis posterior tendon dysfunction.