using System;

using System.Collections.Generic;

using System.Linq;

public class Leg

{

    public int LegId {get;set;}

}

​

public class Program

{

    public static void Main()

    {

        var l1 = new Leg {LegId = 7};

        var l2 = new Leg {LegId = 0};

        var l3 = new Leg {LegId = 8};

        var list = new List<Leg>{l1,l2,l3};

        var sorted = list

            .Select(x => x)

            .OrderBy(x => x.LegId == 0)

            .ThenBy(x => x.LegId);

        foreach(var x in sorted)

        {

            Console.WriteLine(x.LegId);

        }

    }

}