SLR - November 2020 - Christine C. Palma

Do Patient Positioning and Portal Placement for Arthroscopic Subtalar Arthrodesis Matter?

Reference: Shamrock, Alan G., et al. "Do Patient Positioning and Portal Placement for Arthroscopic Subtalar Arthrodesis Matter?." Orthopedic Journal of Sports Medicine 8.7 (2020): 2325967120926451.

Level of Evidence: IV

Scientific Literature Review

Reviewed By: Christine C. Palma, DPM
Residency Program: UF Health Jacksonville – Jacksonville, FL

Podiatric Relevance: Subtalar joint arthrodesis is a common procedure for patients suffering from advanced arthritis of all types. First described in 1992, the arthroscopic approach for this procedure has good outcomes while limiting surgical site morbidity and neurovascular compromise from excessive dissection. The purpose of this study was to determine if patient positioning and portal site placement showed differing outcomes concerning complications with subtalar joint fusion.

Methods: This is a systematic review which included articles that reported complication rates and a description of the operative technique for arthroscopic subtalar joint fusion. Twenty studies were included in this analysis. Patients from each study were categorized into three groups based on surgical technique. Groups were as follows: Lateral group which included patients in the lateral decubitus or supine position, two portal prone group, and the three portal prone group. This included 484 feet in total. Rate of complications related to portal placement, nonunion rate, rate of painful hardware, and any additional surgeries were recorded. 

Results: Mean AOFAS score improved from 46.3 to 81.6 among all studies. Subtalar joint fusion was seen in 95.8 percent of cases at a mean of 10.9 weeks. Complication rates were not significantly different between any of the groups concerning the following: rate of complications secondary to portal placement, rate of painful hardware, rate of repeat surgery. There was a significantly higher rate of nonunion seen in the two portal prone group at 8.1 percent when compared to the lateral group at 1.1 percent.

Conclusions: While the majority of complication rates found between the three groups were not significantly different, nonunion rates between the two portal prone group and the lateral group were. While unclear, authors of the study theorize that a two portal prone group is too limited to adequately prep the joint to allow for fusion. A third portal offers the surgeon the advantage of using it as a way to open the joint further with blunt instrumentation. Proponents of the two portal prone group cite neurovascular safety as the major advantage with the posteromedial and posterolateral portals. However, in this study, there was no different in neurovascular compromise. A third additional portal would be advantageous and warranted for arthroscopic subtalar joint preparation based on the results of this meta-analysis. 

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