Cartilage T2 mapping with loading during MR imaging enabled the detection of site-specific changes in cartilage T2 in dysplastic hips.

In hip dysplasia, acetabular cartilage damage was probably occurred in the antero-superior lateral area. The LM ratio may be a sensitive index to quantify early cartilage damage associated with extent of labral disorders.

We examined the clinical efficacy of alendronate treatment for hip osteoarthritis using multiple outcome measures. Fifty patients with symptomatic hip osteoarthritis were enrolled in this prospective trial. The patients were randomly assigned to an alendronate group (35 mg/week alendronate and 600 mg/day calcium lactate) or a control group (600 mg/day calcium lactate) for 2 years. The groups were compared with regard to the following five parameters. The primary outcome measures are the following: (1) the Western Ontario and McMaster Universities (WOMAC) osteoarthritis pain score and the visual analog score (VAS). The secondary outcome measures are the following: (2) joint space width (JSW) measured on radiographs using a semiautomatic computer software, (3) the biochemical markers urinary N-telopeptide of type I collagen (NTX-I) and C-terminal cross-linking telopeptide of type II collagen (CTX-II), (4) dual-energy X-ray absorptiometry of the hip and lumbar spine, and (5) bone marrow edema on magnetic resonance images. The alendronate group showed pain improvement trends in VAS and WOMAC scores, whereas the control group showed worsening of pain. The alendronate group showed significant improvement in WOMAC pain scores after 12 months (p = 0.031) but no significant prevention of structural osteoarthritis progression, defined as a decrease in JSW >0.30 mm or conversion to total hip arthroplasty. There was significantly larger decrease in the biochemical markers and significantly increased bone density in the alendronate group. Alendronate treatment by standard dose for osteoporosis showed clinical efficacy for decreasing pain but failed to show preventive effects for structural progression of hip osteoarthritis.

The response of T2 to change in static loading or alignment varied between the medial and lateral cartilages, and among the deep, intermediate, and superficial zones. These T2 changes were significantly related to the contact pressure measurements. Our results indicate that T2 mapping under loading allows non-invasive, biomechanical assessment of site-specific stress distribution in the cartilage.

Analysis of 3D distribution of femoral cartilage T2 may be valuable in determining the site-specific normal range of cartilage T2 in the healthy knee joint.