Diagnosis of knee instability using sonography.

OBJECTIVE: A sonographic method has been developed to diagnose knee joint instabilities and to gain exactly quantifiable and reproducible measurements. DESIGN: Based on biomechanical considerations, a new positioning device to analyse knee instabilities sonographically has been developed and tested in in vivo studies. BACKGROUND: Common instrumental testing techniques are difficult to reproduce and show a lack of reliability. METHOD: Using sonography the cortical line of the femur and tibia are observed. At the same time a translation of these two partners at the knee joint is provoked in a defined position using the special holding device and under a defined amount of stress. Using this method 142 healthy people, placed in different age groups, were tested to establish standard values for the physiological knee joint translation. A prearthroscopic stability analysis was performed on 101 patients. RESULTS: This study proves that the special device developed, together with the technique used, provides reliable and exact measurements for knee instability in different translation directions. In healthy subjects the lateral compartment always showed a larger translation than the medial compartment. A gradual increase in translation was determined in the age groups over 30 years. A significant difference of 0.0001 was shown between knee stability and instabilities. Moreover, a further differentiation between partial and total ACL ruptures and chronic instabilities was determined. This provides an important advantage not offered by usual instrumental testing techniques. CONCLUSIONS: The ability to diagnose even a very low extent of instability and to differentiate between different kinds of instabilities enables exact controls to be carried out for both conservative and operative treatment.

[Early changes in the hip joint following epiphysiolysis of the femoral head. Results of an MRT study]. / Frühveränderungen im Hüftgelenk nach Epiphysiolysis capitis femoris. MRT-Untersuchungsergebnisse.

With the aim of detecting patients at risk of developing coxarthritis, 34 patients were investigated prospectively by MRI 6-14 years after epiphysiolysis for slipped capital femoral head. In particular, cartilage changes were analysed by gradient-echo sequences. In 40% of the hip joints investigated cartilaginous lesions were present, detectable as irregularity and flattening of contour and more rarely as changes in signal intensity. In contrast, only 18% of the radiographs available revealed any pathology. When pelvic X-rays are normal or reveal slight sclerosis, cartilaginous lesions on MRI are considered early signs of coxarthrosis. This combination was seen especially often in patients with a primarily high angle of dislocation and in those who needed treatment by reposition or osteotomy. Only in 8 of the 17 hip joints showing sclerosis on conventional radiograms, sclerosis was also diagnosed by MRI, possibly because of partial volume and susceptibility effects at high field strength. Even with limited spatial resolution, cartilage examination is warranted in young patients in whom early osteoarthritis can be expected.

[Magnetic resonance tomography of so-called transient osteoporosis. Primary diagnosis and follow-up after treatment]. / Magnetresonanztomographie der sogenannten transitorischen Osteoporose. Primärdiagnostik und Verlaufskontrolle nach Therapie.

Transient osteoporosis or transient bone marrow oedema is a rare cause of acute hip pain that predominantly affects adults of middle and younger age. We report on the MR image in 8 patients with transient bone marrow oedema of the hip and in one patient with affection of the knee joint. In three of these, sympathetic nerve blockade has been performed. The MR image after sympathicolysis is discussed.