HETEROTOPIC OSSIFICATION PROPHYLAXIS FOLLOWING OPERATIVE TREATMENT OFACETABULAR FRACTURE

Eighty seven patients with 88 fractures were retrospectively reviewed to assess the effect of postoperative prophylaxis on the formation of heterotopic ossification (HO). Sixty eight patients with 69 acetabular fractures were followed for an average of 21 months (range, 3-98 mont hs). The grade of HO was assessed using the Brooker classification sys tem. Thirty four fractures had no prophylactic treatment, 30 were trea ted prophylactically with indomethacin, two with radiation therapy, an d three with both indomethacin and radiation. Twenty (59%) of 34 untre ated fractures developed HO, of which nine (26%) were Grade III or IV. Thirteen (43%) of 30 fractures treated with indomethacin developed HO , of which 5 (16%) were Grade III and none were Grade IV. Twenty one o f 24 fractures were stabilized through the extended iliofemoral approa ch; 13 of these had no prophylaxis. Eleven of the 13 developed HO; eig ht were Grade III or IV (62%). Seven of eight fractures treated with i ndomethacin following the extended iliofemoral approach developed HO; one was Grade III (13%) and none Grade IV. There was no significant di fference between 13 patients who were not treated prophylactically and 18 indomethacin treated patients stabilized through the Kocher-Langen beck approach. Only one of 11 patients had HO (Grade I) following an i lioinguinal approach. Postoperative radiation therapy, with or without indomethacin, resulted in three patients with Grade 0 HO (all radiate d 1-4 days post surgery), one with Grade II (radiated postoperative Da y 8), and one with Grade III HO (significant delay in surgery with pre operative Grade III HO of the hip). There was a statistically signific ant reduction of HO in patients treated prophylactically with indometh acin following the extended iliofemoral (p = 0.04). The current study appears equivocal on the efficacy of indomethacin following the Kocher -Langenbeck incision. HO prophylaxis is not required following use of the ilioinguinal approach.