Pain Pumps (continuous local infusion)

The advantages of local infusion pumps are well proven, lower narcotic use, earlier ambulation, etc.

The pumps in use are 4mL/hr (flow rate not adjustable, catheter placement and med concentration are only variables) continuous infusion (200mL capacity refillable) and are used with Naropin or Marcaine. Surgeons are reluctant to use the pumps because they are unsure of effectiveness and questions frequently asked are:

How much loading dose do I use (how close to lethal is safe)?
Do I need a nerve block as well?
Do I use higher concentration meds for larger compartments (ie joint space in knee is larger than shoulder or elbow)?
Can I position a drain within the joint capsule as well as the pump catheter or will the medication be removed before it is absorbed?
Which is more effective, the catheter be positioned near fat, muscle or bursa?
Is there any chance of chrondrolysis?
Will the low infusion rate be sufficient to alleviate the pain?

Any information would be much appreciated. Or suggested articles would be great.