Periarticular new bone formation associated with head injuries
Groswasser, Z.; Cohen, M.; Groswasser-Reider, I.
Harefuah 110(7): 323-326
1986
ISSN/ISBN: 0017-7768 PMID: 3089886 Document Number: 280568
Periarticular new bone formation (PNBF) accompanies various neurological conditions. Among the more common ones are head injuries (HI), spinal cord injuries, poliomyelitis and toxic conditions such as carbon monoxide poisoning. The incidence is not known and varies according to the population studied. HI associated with coma is very common, and in a series of such cases over 70% had PNBF. The incidence in the present study of 185 HI patients was low (6.5%), most probably due to the fact that most of the patients had been in coma for less than three weeks. The etiology of PNBF is not known and histopathological studies have been of no help. In most patients high levels of alkaline phosphatase are found during the active phase, which is usually over in a year. Endocrinological studies in comatose HI patients were normal, though those with PNBF had a abnormally high growth hormone response after l-dopa and TRH stimulation. On X-ray, PNBF is noted as early as the sixth week post-trauma. The early finding is an ill-defined, cotton-wool, periarticular mass that becomes organized and very often merges with the adjacent bones forming bony bridges that anklylose the joints. Only large joints are known to be affected, the hip and elbow joints in our case. A highly unusual involvement of the cervical spine, verified by computerized tomography, is described in a HI patient, who had involvement of other joints as well. Since the etiology is unknown, there are no prophylactic measures. Surgical removal proved to be only partially successful and there was a marked tendency to recurrence. Sodium ethidronate was tried as a possible prophylactic agent and post-surgical removal of ankylosing PNBF met with only limited success. PNBF complicates the rehabilitation of patients since they may recover from their neurological deficits but suffer severe locomotor restriction due to the PNBF.