Study Says Inflow/Outflow Arthroscopy Pump Saves Money

In short

Arthroscopic pumps have been around since surgeons realised they needed more joint pressure in order to create space in which to operate and a clear field to visualise anatomical features. In Europe, FMS became the undisputed king of arthroscopy pumps with its twin rotor inflow/outflow device, which gave the surgeon total control over the joint space and pulled out the debris at the same time as it was pushing in clear saline. Now a new paper has been published which supports what FMS knew all along, which is that its system uses less saline than inflow-only models with consequent cost savings significant enough for high volume arthroscopy centres to take note.


The FMS inflow/outflow arthroscopic pump has been around for over fifteen years virtually unchanged, which rather speaks for itself, and the French company was acquired by DePuy Mitek in, from memory, about 2004/5. The concept on which the device was based was that by not only pushing fluid into a joint, but also pulling it out of the joint the operative field would be kept clearer of surgical detritus than in a conventional inflow only device. This was indeed the case, many arthroscopists agreeing that this pump represented the gold standard in maintenance of joint pressure and clarity of view. Furthermore by keeping the joint clear in this way surgeons could use lower distention pressure and combining this feature with the tubing set to capture the outflow, keep their feet drier.

Back in the early days it was also mooted that, however counter-intuitive it sounded, by keeping a flow going through the joint at a lower pressure than that required by an inflow only pump such as Dyonics’ Intelijet, less fluid would be used during the case, with attendant cost savings. On the whole however this argument fell on deaf ears because the surgeon was almost completely unconcerned about the cost of saline used, it being far less important a consideration than his/her ability to perform the procedure with a clear view of proceedings.

It makes one realise just how times have changed then, when we see a new publication trumpeting the cost saving to be had by using this type of pump, now badged the DePuy Mitek FMS DUO®+ Fluid Management System. The work, authored by Anthony Pachelli, MD et al from New Mexico Orthopedic Associates and presented at this year’s AANA congress, suggests that the additional cost of outflow tubing required by this type of pump is more than offset by the reduction in fluid required, making a net saving to a high volume arthroscopy centre of almost $10k per year.

Study findings

Researchers from New Mexico Orthopedic Associates retrospectively analysed the financial impact of switching from a standard in-flow only arthroscopy pump to the Duo inflow/outflow controlled pump in its high volume facility.

Costs were calculated by measuring the absolute volume of saline used, the number of tubing sets used, and the average dollar cost for both saline and tubing.

• Annual cost savings for fluid was $28,387 in favor of the FMS DUO pump
• Annual cost savings for tubing was $18,872 in favor of the standard in-flow only pump
• Annual overall cost savings were $9,515 in favor of the FMS DUO pump

Shoulder Arthroscopy Findings in Two Week Sampling

Median total cost per procedure nearly 20 percent higher for in-flow only pump at $70.92 compared with $50.96 for FMS DUO pump.

Knee Arthroscopy Findings in Two Week Sampling

Median total cost per procedure nearly double for in-flow only pump at $79.83 compared with $39.89 for FMS DUO pump

We say

Clearly the entirety of costs need to be taken into account, including the hardware. The FMS Duo pump, with its twin motors was always a more expensive piece of kit than the single motor models in terms of list price, so the potential savings hinge somewhat on whether the various companies are placing or selling their hardware. Nonetheless it’s clear that the concept of circulating fluid through the joint rather than relying on inflow pressure only to do the job has a consumable cost saving as well as offering advantages in terms of surgical control over the operative field and also avoiding overly high joint pressure and fluid extravasation.

One observation on the knee arthroscopy saving would be the question of whether a pump is actually required at all for most cases. Unlike shoulder procedures the knee joint is easier to access and manipulate and procedures are typically less complex, making routine use of a pump less of a given requirement, except where extensive shaver use is indicated.

In conclusion then, we’re bound to applaud the study at the same time as we marvel that its taken this long to see work like this. Welcome to a future in which the medical profession needs to look under every rock to find economies.

Source: DePuy Mitek

Reference: Pachelli, A., Bansal, M., Conner, D. (2012). Cost analysis of switching from an in-flow only irrigation pump to an in-flow/out-flow fluid management system. Arthroscopy Association of North America.