Disuse osteoporosis of the upper limb: assessment of thirty patients

Osteoporosis is a multifactorial skeletal disorder characterized by the decrease of bone mass and the alteration of bone microarchitecture that leads to the increase of fracture risks. Traditionally, osteoporosis has been classified into primary and secondary osteoporosis. Primary osteoporosis refers to osteoporotic conditions which are not related to other chronic illnesses and is usually associated with aging and decreased gonadal function, such as decreased level of estrogen, whereas secondary osteoporosis is the type of osteoporosis caused by other health problems. Disuse is one of the many reasons inducing bone loss and resulting in secondary osteoporosis. The disuse osteoporosis appeared for the first time in the literature in 1974 when Minaire reported some histomorphometric analysis of iliac crest bone biopsies performed after a spinal cord injury. The most common skeleton sites in which disuse osteoporosis can be observed are knees and ankles. THERE ARE THREE CLINICAL SITUATION IN WHICH THIS DISEASE CAN BE OBSERVED: neurological or muscular disease that causes a pathological and prolonged immobilization. The most frequent is caused by a spinal cord injury, long term bed rest or space flight that causes the immobilization linked to changes in mechanical environment and experimental immobilizations in healthy subjects. Physical exercise is essential for increasing or maintaining bone mass and strength. In our study we wondered if the disuse of the upper limbs of a certain entity, lasting for a long time, can cause a decrease in BMD quantifiable with a densitometric evaluation of the distal radius and with an evaluation of the humeral cortical index such as to define a real osteoporosis from disuse. We analyzed 30 female patients without secondary osteoporosis older than 60 years: everyone underwent to vit D evaluation, densitometric exams of spine, hip and distal radius, Constant score and femoral and humeral cortical index evaluation. We observed that the distal radius BMD and humeral cortical index were worse in patients with low upper limb functionality than in patients with normal shoulder function. The results of this study suggest that humeral cortical index and radial BMD can be useful methods of upper limb bone density evaluation and that they can be useful to select a correct surgical treatment in orthopaedic and traumatologic diseases.