Total hip arthroplasty for fused hips.

Arthrodesis of the hip has been used extensively in the past as the procedure of choice for many disabling diseases of the hip.1-4 A successful arthrodesis should provide a stable, painless hip. After hip fusion, patients usually have a short leg and will walk with a slightly slower pace than an individual with normal hips. They will likely walk with a perceptible limp and a gait described as asymmetric and arrhythmic, although they will be pain free in the affected hip. The majority of patients will consider their overall activity level to be limited.5 The most troublesome limitation of activities of daily living involves those that require hip fl exion, eg, bending, sitting, bicycling, or putting on socks or shoes. Sitting can be uncomfortable for prolonged periods or in cramped spaces.6 In the long term, most patients develop symptomatic arthritis in the spine, ipsilateral knee, and contralateral hip, usually due to the abnormal stress to which these regions are subjected.7,8 Furthermore, the position of hip fusion usually entails 5 to 7 of adduction, which interferes with normal sexual function in women. Many problems are associated with such surgery, including altered anatomy, atrophy of the abductor musculature, and limb-length discrepancy. This article presents the results of a retrospective study converting 16 fused hips to total hip arthroplasty (THA), either surgically (arthrodesis) or spontaneously following juvenile rheumatoid, ankylosing spondylitis, or septic arthritis. Meticulous preoperative planning is required for proper positioning of the acetabulum, leg-length restoration, and abductor moment arm restoration.9