Comparisons between ankle distraction arthroplasty and supramalleolar osteotomy for treatment of post-traumatic varus ankle osteoarthritis

BACKGROUND: Ankle distraction arthroplasty and supramalleolar osteotomy were both options for post-traumatic varus ankle arthritis (VAA), but their comparative effectiveness was scarcely reported. This study aimed to compare the outcomes of two operative methods for treatment of Takakura-Tanaka stage 3 post-traumatic VAA. METHODS: This was a retrospective study, comprising 73 consecutive patients who presented with Takakura-Tanaka stage 3 post-traumatic VAA treated by either ankle distraction arthroplasty (n = 32) or supramalleolar osteotomy (n = 41) from January 2016 to December 2019. All patients had a minimum 24-month follow-up assessments. The outcome measures were visual analog scale (VAS), the American Orthopedic Foot & Ankle Society (AOFAS) ankle-hindfoot scores, complications, patient-rated overall satisfaction and ankle function. RESULTS: At an average of 32 months (range, 24–52 months) follow-up, significant improvement was observed for VAS, AOFAS, range of motion (ROM) and most radiographic parameters (except for TAS and TLS for ankle distraction arthroplasty group) compared to preoperative baselines (p < 0.05) for both groups. However, both groups did not differ significantly in terms of VAS or AOFAS, excellent and good rate (78.1% versus 85.4%, p = 0.422), overall rate of postoperative complications (28.1% vs. 17.1%, p = 0.257), or various radiographic parameters (e.g. tibial anterior surface angle, talar tilt angle and tibial lateral surface angle) (all p > 0.05). The ankle distraction arthroplasty group had a better postoperative ankle motion than did the supramalleolar osteotomy group, in terms of plantarflexion (37.8 ± 4.2 vs. 30.4 ± 3.6, p = 0.006), dorsiflexion (36.5 ± 6.4 vs. 28.3 ± 5.5, p = 0.004), varus (32.1 ± 4.5 vs. 27.1 ± 3.1, p = 0.017) and valgus (28.4 ± 3.7 vs. 25.2 ± 2.8, p = 0.046). CONCLUSIONS: Both operative treatments are effective for Takakura-Tanaka stage 3 post-traumatic VAA. In practice, individualized treatment option tailored to the ankle condition and patients’ specific need should be considered. Level of evidence: III, retrospective comparative series.