Relationship Between Tibiotalar Joint Space and Ankle Function Following Ankle Surgery

Background: Joint-preserving procedures of the ankle may postpone the need for ankle arthrodesis (AA) or total ankle replacement (TAR). The challenge for the surgeon is to determine which patients may benefit from these joint-preserving procedures. We hypothesized that patents with less than 2 mm of ankle joint space on preoperative radiographs would report inferior outcomes following joint-preserving surgery compared with those with 2 mm or greater joint space. Methods: Patients 18 years of age or older treated with joint-preserving ankle surgery with a minimum of 2 years of follow-up were considered for study inclusion. The ankle joint space was measured on standardized weightbearing preoperative radiographs. At follow-up, patients completed questionnaires including the Foot and Ankle Ability Measure (FAAM) Activities of Daily Living (ADL) and Sports subscales, the Short Form-12 (SF-12) Physical Component Summary and Mental Component Summary, the Tegner Activity Scale, and satisfaction with outcome. Results: A total of 251 patients were included in the study. Forty-three patients had an ankle joint space of less than 2 mm. Compared with the 208 patients with an ankle joint space of 2 mm or greater, they had inferior FAAM ADL, FAAM Sports, and SF-12 Physical Component Summary scores (P = .001, P = .001, and P = .006, respectively). Additionally, a statistically significant positive correlation between joint space distance and the FAAM ADL (P = .012, r = 0.158), FAAM Sports (P < .001, r = 0.301), and SF-12 Physical Component Summary (P < .010, r = 0.163) scores was found. Conclusion: Patients with a preoperatively narrowed ankle joint space of less than 2 mm had significantly lower outcome scores following joint-preserving ankle surgery compared with patients with preserved ankle joint space. These results may assist clinicians in selecting patients who may benefit from ankle joint–preserving procedures, as well as counseling patients with a narrowed ankle joint space regarding expected outcome after joint-preserving ankle surgery. Level of Evidence: Level II, prognostic comparative study.