To evaluate differences in the outcome of arthroscopic treatment for posterior ankle impingement syndrome (PAIS) between os trigonum (OT) and Stieda's process (SP) cases.
Thirty consecutive patients (32 feet) treated in our Institution for PAIS with posterior arthroscopy were prospectively enrolled in the study from December 2012 to July 2019. Indications were patients with PAIS with persistent symptoms following conservative management. Exclusion criteria were the coexistence of concomitant pathologies and patients who underwent additional surgical procedures. An independent investigator interviewed and evaluated the patients according to the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score and Foot Function Index (FFI) preoperatively, at 6-month and 12-month follow-up.
Patients undergoing arthroscopic treatment for bony PAIS had an overall significant AOFAS score and FFI improvement from their preoperative scores at 6-month follow-up, except for AOFAS scores in the SP group. Similarly, a significant improvement in AOFAS score and FFI was observed from the 6-month to 12-month follow-up in all groups. When comparing the OT vs. SP group at 6-month follow up, OT group had significantly better AOFAS (86.79 ± 11.17 vs. 75.07 ± 17.48, P = 0.026) and FFI (25.93 ± 30.81 vs. 59.50 ± 46.27, P = 0.019) outcomes when compared to the SP group. No differences were found when comparing both groups' AOFAS score and FFI at 12-month follow-up.
When comparing patients undergoing OT excision or SP resection, a faster recovery was observed in the OT group at 6-month follow-up.