Selective COX-2 inhibitors significantly reduce the occurrence of heterotopic ossification after hip arthroscopic surgery

A well known complication after hip arthroscopic surgery is heterotopic ossification (HO), the presence of bone in soft tissue. This complication can be as prevalent as 44% of patients when no prophylactic intervention is given. Although it is not totally understood how HO occurs, it is known that mesenchymal cells provide the origin for this, and they are activated by inflammatory mediated response in injured tissues. Low-dose irradiation and nonsteroidal anti-inflammatory drugs are the two most commonly used interventions for this problem of reducing and preventing HO. This study hypothesized that postoperative HO prophylaxis using 600 mg of etodolac once daily for two weeks would significantly reduce risk of HO in patients after surgery in comparison with a groups of patients who were treated by the same surgeon who did not receive NSAID prophylaxis. Their ultimate goal of the study was to evaluate the effectiveness of short-term selective COX-2 inhibitors (specific NSAID) when they are being used prophylactically for HO.

In this retrospective analysis of data gathered from a cohort of patients who underwent surgery by the same surgeon for the same reason, femoroacetabular impingement.  Although the study started out with 263 patients patients, 163 were included in the final analysis because 100 of them had to be excluded for various reasons including lost to follow-up, previous hip surgery or HO, and not meeting inclusion criteria. 100 patients were assigned to the control group and 63 were included in the group that received COX-2 inhibitor prophylaxis. In the control group, 35 of 100 patients developed HO. The patients were tested for HO 2 weeks, 6 months, and 1 year after surgery. The data did exhibit a significant difference between the control and study groups, as there were no patients in the study group who developed HO. This is the first study to ever look at a dose this low, half of the maximum, in attempting to prevent HO with this specific medication. It is significant that this research is able to show a short-term, selective NSAID can be used to effectively prevent HO in this patient population because it gives the patients much less of a risk of developing the GI side effects that are so closely associated with traditional NSAIDs.

It is interesting how choosing between medications in the same class can often be very significant when treating a patient and trying to keep them as healthy and happy as possible. In what other classes of drugs can this be significant?
Rath E, Warschawski Y, Maman E, et al. Selective COX-2 inhibitors significantly reduce the occurrence of heterotopic ossification after hip arthroscopic surgery. Sports Med. 2016;44:677-81.

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