Ankle osteoarthritis results in a low quality of life. The most accepted treatment currently is ankle distraction arthroplasty. The aim of the present study was to determine and to obtain an overview of other clinical outcomes.
A literature search of MEDLINE (PubMed), EMBASE (Ovid) and the Cochrane Library was performed on 18 May 2020. Methodological quality was assessed by two independent authors using the methodological index for non-randomized studies (MINORS) criteria. The primary outcome was an annual revision rate (ARR), calculated using either a cumulative revision rate or using the mean follow-up. The ARRs were log-transformed and presented in a forest plot, using a random effects model and weighted by the inverse variance. Secondary outcomes included the AOFAS, VAS, range of motion, and complications and were analysed using a simplified pooling technique.
The literature search resulted in 229 articles of which 9 studies, comprising 570 patients, were included. The patients had a mean age and follow-up of 46.4 years (range of means: 39.6-68.2) and 35.2 months (range of means: 24-48), respectively. The overall methodological quality was fair. Primary outcome analysis resulted in a pooled annual revision rate of 4.6% (95% CI, 2.7% to 7.7%). Pooling of the secondary outcomes resulted in a dorsiflexion improvement of 1.0o (4.4o to 5.4o, n=122). Plantarflexion decreased with 3.8o (33.4o to 29.6o, n=122). VAS and AOFAS scores improved with 4.6 (from 7.1 to 2.5, n=142) and 25.0 (from 54.5-79.5, n=211), respectively.
Ankle distraction arthroplasty results in a low annual revision rate, with improved AOFAS scores. Dynamic distraction resulted in a higher annual revision rate, although there was limited evidence available. Complications rates are high but exist mainly out of treatable pin-tract infections.