SharePoint - Powershell replacement for the old STSadm RepairContentDatabase
Powershell replacements are extremely useful.
Test-SPContentDatabase gives you much of interest.
However the key item you were looking for is the .REPAIR method.
Get-SPContentDatabase | ForEach-Object { $_.Repair($true)}
or use $false to just report and not repair.
This is the same function as the STSADM cmdlet, but better because it pipelines all the ContentDB's.