Radiographic patterns and response to corticosteroid hip injection

OBJECTIVES—A prospective, open study of corticosteroid hip injection (CHI) was performed to determine if different radiological patterns of arthritis vary in their response. METHODS—Forty five patients (15 with rheumatoid arthritis, 27 with osteoarthritis, and three with anklyosing spondylitis) underwent hip injection with 80 mg methyl- prednisolone and lignocaine under x ray control. Outcome was assessed at two, 12, and 26 weeks for pain, range of hip movement, and graded functional questionnaire. Patients estimated their pain in four components, night pain, rest pain, weight bearing, and referred pain, each measured by 10 cm visual analogue score and summed to give a total score out of 40 cm. Hip radiographs were evaluated blindly for pattern and severity of arthritis, as well as for progression between 0 and 26 weeks. RESULTS—Median total pain score decreased from 29 cm at baseline to 22 cm at two weeks (p=0.0001), 24 cm at 12 weeks (p=0.03), but had returned nearly to baseline by 26 weeks (25 cm, p=0.3). Greatest improvement was seen for night pain. Mean range of internal rotation increased from 16 to 28 degrees at two weeks (p=0.03) and 23 degrees at 12 weeks (p=0.06). Functional ability did not change. Hips with an atrophic pattern of arthritis on plain radiography gained negligible pain relief at two weeks compared with hips with a hypertrophic or mixed bone response (p=0.04). The degree of pain relief was similar in patients with OA and RA, and was not influenced by radiographic severity or by the direction of migration of the femoral head. CONCLUSION—Pain and internal rotation improve for up to 12 weeks after CHI. CHI offers a useful and safe therapeutic option for patients with hip arthritis, with the exception of those with a purely atrophic radiological pattern.