(AAOS2015) The first study to assess the effect of steroid injections on the hip joint suggests that they may hasten joint degeneration, but the co-injected local anesthetic is also suspect.
They may be recommended in current clinical guidelines, but two studies reported at the American Academy of Orthopaedic Surgeons annual meeting in Las Vegas present reason for serious concern about steroid injections into the hip joint.
Within a mere six months of receiving ultrasound-guided intra-articular hip injections with the corticosteroid triamcinolone acetate and lidocaine, a retrospective study at the University of North Carolina (UNC) at Chapel Hill has shown, all but one of 33 consecutive patients showed marked decreases in joint space width visible on standard radiographs. Bone-on-bone degeneration developed in nearly a third.
Another study, this one from investigators at the Mayo Clinic, revealed that intra-articular corticosteroids have a "profound, yet differential" dose-dependent impact on mesenchymal stem cells, also suggesting a "potentiation" of joint disease.
The study presented by UNC medical student Matthew Horn appears to be the first to show a detrimental effect of steroid injections on the hip joint.
"Of course, the natural history for hip [degenerative joint disease] is for progression over time," lead author Daniel DelGaizo, MD told Rheumatology Network. But given the "rate and magnitude of the degeneration," in their cohort, "we felt it needed to be reported ... Some of the degeneration is so severe with bone loss and subluxation that it mimics what we see in Charcot arthropathy."
Patients received 40 mg triamcinolone acetonide and 0.5 mL lidocaine. The local anesthetic may be partly to blame, speculated DelGaizo, who is assistant professor of orthpaedic surgery. Of course he urges prospective studies to pursue the question.
Previous research has shown that corticosteroids have a detrimental effect on chondrocytes and that local anesthetics are cytotoxic to mesenchymal stem cells, observe medical student Cody Wyles and his Mayo Clinic coauthors in a report of their newly published study that they also reported at the AAOS meeting.
Triamcinolne is only moderately damaging, according to their study. The team exposed human mesenchymal stem cells cultured from 20 patients undergoing hip replacement to eight different titrations of betamethasone, dexamethasone, and triamcinolone. The steroid decreased the viability of the stem cells in a "clear dose-response fashion," they found, with significantly worse effects of betamethasone. Evidently dexamethasone was least detrimental to stem cell viability.
"Young patients and those without imminent need for reconstructive procedures may benefit from this consideration," the researchers observe in Clinical Orthopaedics and Related Research.1
1. Wyles CC, Houdek MT, Wyles SP et al. Differential Cytotoxicity of Corticosteroids on Human Mesenchymal Stem Cells. 2015; 473:1155-64. doi: 10.1007/s11999-014-3925-y. Epub 2014 Sep 4.