Authors: AL McIntosh MD, AD Hanssen AD, DR Osmon, DE Wenger MD
Addresses: 200 First St. SW Rochester, MN 55905
Title: The outcome of primary total hip arthroplasty after receiving intra-articular steroid injection.
Purpose: To determine the outcome of primary total hip arthroplasty (THA) for the treatment of osteoarthritis after receiving an ipsilateral hip intra-articular steroid injection compared to a control group of primary THA.
Methods:This is a retrospective matched cohort study. Between Jan. 1998 and May 2002, 224 primary THA were implanted for the diagnosis of osteoarthritis in 219 patients that pre-operatively received an ipsilateral hip intra-articular steroid injection within one year of replacement. The control group consisted of 224 primary THA implanted in 220 patients who did not receive a pre-operative hip intra-articular steroid injection. The patients were matched by gender, age, height, weight, year of THA, and surgeon. The study group included 93 men and 131 women with a mean age of 70 (60-80) years. The control group included 92 men and 132 women with a mean age of 69 (59-79) years. The mean time interval between steroid injection and THA was 119 (21-217) days. The mean clinical follow-up was 2.7 years in the study group and 2.6 years in the control group.
Results: In the study group, there were 6/224 dislocation (2.7%) compared to 5/224 (2.2%) in the control group (p= 0.79). There were 3/224 (1.3%) deep and 11/224 (4.9%) superficial infections in the study group compared to 1/224 (0.45%) deep and 8/224(3.6%) superficial infections in the control group, p =0.31 and p = 0.39, respectively. Both the study and control groups had 1/224 (0.45%) revision for aseptic loosening of both the femoral and acetabular components (p = 0.98). The relative risk for deep infection was 2.88 when comparing the study to the control group. None of these findings were statistically significant. This may be due to sample size or chance.
Discussion: This study demonstrated that receiving an ipsilateral intra-articular steroid injection within one year of subsequent THA did not have a statistically significant effect on post-operative rates of dislocation, deep and superficial infection, or aseptic loosening. However, the mean time from steroid injection to THA in the deep infection subgroup was 44 days, and the risk of deep infection was 2.88 times higher in the study group. Therefore, we recommend using caution and judgment prior to performing an intra-articular steroid injection to conservatively treat hip osteoarthritis if THA is being contemplated in the near future.
Significance: We know of no other reports in the literature addressing the outcome of THA for the treatment of osteoarthritis after receiving an ipsilateral intra-articular steroid injection.