Intra-articular hyaluronic acid injections less than 6 months before total hip arthroplasty. Is it safe? A retrospective cohort study in 565 patients.

Abstract Background Intra-articular hyaluronic acid (IAHA) can be injected into an osteoarthritic hip joint to reduce pain and to improve functionality. Several studies report IAHA to be safe, with minor adverse effects that normally disappear spontaneously within a week. However, intra-articular corticosteroids prior to total hip arthroplasty (THA) have been associated with increased infection rates. This association has never been investigated for IAHA and THA. We aimed to assess the influence of IAHA on the outcome of total hip arthroplasty (THA), with an emphasis on periprosthetic joint infection (PJI). Methods At a mean follow-up of 52 months (±18), we compared complication rates, including superficial and deep PJIs, of THA in patients who received an IAHA injection ≤6 months prior to surgery (injection group) with that of patients undergoing THA without any previous injection in the ipsilateral hip (control group). One-hundred thirteen patients (118 hips) could be retrospectively included in the injection group, and 452 patients (495 hips) in the control group. Results No differences in baseline characteristics nor risk factors for PJI between the two groups were found. The clinical outcomes in terms of VAS pain scores (1.4 vs. 1.7 points, p=0.11), modified Harris Hip Scores (77 vs. 75 points, p=0.09) and Hip disability and Osteoarthritis Outcome Scores (79 vs. 76 points, p=0.24) did not differ between the injection group and the control group. Also, complications in terms of persistent wound leakage (0 vs. 1.2%, p=0.60), thromboembolic events (0 vs. 0.6%, p=1.00), periprosthetic fractures (1.7 vs. 1.2%, p=0.65) and dislocations (0 vs. 0.4%, p=1.00) did not differ. However, in the injection group there was a higher rate of PJIs (4% vs. 0%, p Conclusion Our findings suggest that IAHA performed 6 months or less prior to THA may pose a risk for increased rates of PJI. We recommend refraining from performing THA within 6 months after IAHA administration