Posterior Ankle and Hindfoot Arthroscopy: Complications and Posterior Ankle Impingement Pathologies

CATEGORY: Ankle, Arthroscopy, Hindfoot, Sports INTRODUCTION/PURPOSE: Posterior ankle/hindfoot arthroscopy (PAHA) is an established surgical option for treating pathologies, of posterior ankle and subtalar joints, which otherwise would require open incisions. Arthroscopic procedures are less invasive, provide magnified visualization and allow earlier rehabilitation and return to activity. Many studies have reported outcomes after PAHA, however only two studies have reported complications in larger cohorts. Although posterior ankle impingement (PAI) is a common indication for PAHA, it is a non-specific diagnosis. The aims of our study are 1) to report the complications after posterior ankle arthroscopy. 2) Delineate the structures involved in PAI into zones based on arthroscopic findings including bone impingement from the talus or tibia, soft tissue impingement from the PITFL, PTFL, inter-malleolar ligament, posterior deep deltoid ligament and synovitis. METHODS: We reviewed the chart for demographic details, diagnosis, arthroscopic findings, and complications in a consecutive series of 250 PAHA in 237 patients (94 males,143 females, mean age 34.3 years) who had surgery between 2008 and 2016 and excluded those who had Haglund excision. The indications were PAI (95 ankles), subtalar arthritis/coalition/nonunion(21/12/5), flexor hallucis longus (FHL) stenosis/tenosynovitis/contracture(22/9/5), osteochondral lesions(14), and others(14)(Table 1A). There were 67 ankles with PAI and at least one other coexisting condition. For patients with PAI, we catalogued the specific anatomic etiologies of impingement. To investigate a priori factors predictive of neurological complication after PAHA, unadjusted and multivariable regression techniques were utilized. Sparse events sensitivity analysis was tested by fitting models with Firth log-likelihood approach; penalizing estimates for first-order bias correction and stability of regression coefficients. To control for clustering of outcomes across surgeons (n=3), estimates were assessed by fitting the primary log-binomial model with generalized estimating equation. RESULTS: Complications: sensory nerves (10) (5 tibial/branches, 5 sural), portals (4) (painful/nodular (1), draining>1week (3)). Achilles pain (1) DVT (1). Nerve symptoms after 6 months (3) had; transection of the sural nerve (1), sural neurolysis (1) or tarsal tunnel release (1). (Table 1B) In unadjusted analysis, advancing age (OR: 1.04; p=0.029) and accessory portal (OR: 15.64; p<0.001) were associated with neurological complication. In multivariable regression models controlled for confounders, accessory posterolateral portal usage (OR:12.37; 95% CI: 3.11-49.27; p<0.001) was the most significant driver for neurological complication after PAHA. No significant correlation exists between neurological complications and surgical duration, surgeon, tourniquet time, BMI, FHL release. There were 162 ankles treated for PAI +/- associated conditions. PAI etiologies were grouped into: posterior, posteromedial, posterolateral, subtalar, and combined zones. CONCLUSION: This study supports the safety of posterior ankle/hindfoot arthroscopy for the treatment of numerous pathologies with an overall complication rate of 6.4% (16/250). There were no infections, motor nerve or vascular injuries. Complications included sensory nerve symptoms in 10 patients (4%), of which three (1.2%) did not improve and required further treatment. One patient developed DVT which required further treatment. The common pathologies of impingement were able to be grouped into zones that can correlate with physical examination (Table 1C). The ability to visualize the structures with the arthroscope provides greater magnification, detail and precision in the treatment.