STRAIGHT LEGGED Perform partial and total knees with the knee in extension, so the quadriceps remains lax.

Why is sending knee arthroplasty patients home the day of surgery considered the future of joint replacement? I've been doing outpatient total and partial knee replacement to treat degenerative arthritis for more than a decade, pioneering the surgical technique and perfecting management of post-op pain, PONV prevention and DVT prophylaxis. More surgeons and facility leaders are realizing the procedure can be done safely and efficiently in ambulatory settings. They're right, as long as every aspect of patient care, from pre-op to PACU, is performed perfectly.

Everyone's a candidate
Outpatient knee replacement is suitable for most any patient healthy enough for surgery, so we don't deny many patients the care they seek. In fact, I recently operated on a 93-year-old man who went home the same day.

We typically perform 8 knee arthroplasties in a day. Patients who undergo surgery at 7 a.m. are usually ready for discharge between noon and 1 p.m. Those operated on in the early afternoon head home between 5 p.m. and 6 p.m. My hospital mandates that patients must get in and out of bed without nurse assistance, and walk up and down a hallway and stairs by themselves before being released. (Patients complete brief post-op consultations with a physical therapist before being cleared for discharge.) Most patients go home without need of a cane; we give some crutches or, rarely, a walker.

It's critically important to set the expectations of patients and their escorts for same-day discharge. My minimally invasive replacement technique is really a minor procedure, so there's no reason most patients shouldn't be able to go home a few hours after surgery. They and their loved ones need to realize and expect that. They'll be up and walking in PACU. They'll be comfortable and medically stable. They'll be ready to go home after a short stay in recovery. But if unforeseen medical issues arise during the recovery phase or they can't move around by themselves — rare occurrences in my experience — we'll keep them as long as needed, until they're ready for appropriate and safe discharges.

Less trauma, better results
Unicondylar knee replacement is really a partial resurfacing of the joint. A small skin incision is made on whichever side of the knee — the inner or outer aspect — needs resurfacing. A cut is then made through the articular capsule, the structure that holds the knee in place. No muscle, tendons or ligaments are touched. Small cuts around the knee remove the diseased segment of the bone, which is then capped with a metal prosthesis that goes on the bottom (tibia) and top (femur). Finally, a small ultra-high molecular weight (UHMW) polyethylene plastic piece is placed between the caps. Total knees are done much the same way. A cut is made through the capsule, sparing muscle, tendons and ligaments. Instead of addressing half the knee, however, the entire joint is resurfaced and capped, including the back of the patella.

Key to my success in partial and total knees is performing the procedure with the knee in extension, with the quadriceps lax so I'm not pulling or tearing the muscle to access the joint. Many surgeons perform knee replacements with the knee bent all the way, hyperflexed so the heel touches the glute. In that position, the quad is stretched, forcing surgeons to tug and cut it in order to reach the joint.

With the knee in extension, the quad muscle is loose and easily pushed to the side. By not cutting muscle or pulling and tearing the remaining muscle, you limit post-op pain. In traditional knee arthroplasty, the joint is also dislocated when the 2 ends of the bone are torn from each other. That causes a great deal of trauma to the knee, and therefore more post-pain and potential for further complications (see "Why Muscle-Sparing Techniques Matter" on page 34).

Typical partial knee procedures last 45 minutes, from incision to closure. Total knees can be done in about an hour. The procedures require standard battery-operated drills and saws, and partial and total knee systems. What's most important is working with instruments designed for minimally invasive approaches to the joint that let surgeons place the knee platform's components through an incision approximately 9cm long.

Managing pain and complications
Patients must be medically stable, comfortable and ambulatory without assistance before being sent home. Managing their pain and PONV and DVT risks achieve those goals.

• Pain. People have different pain tolerances, so we tailor pain control medications to each patient, toeing the fine line between making them comfortable and keeping them alert enough to ambulate after surgery and recover quickly enough for timely discharges. We assess patients before, during and after procedures to determine the minimal pain medication needed to get them through surgery comfortably and efficiently. The goal is to tailor doses so that we control discomfort and they're ready to start moving on their own shortly after surgery.

SAME-DAY SURGEON Dr. Berger (left) performs up to 9 knee arthroplasties in a day.

Most patients take 10mg of oxycodone twice a day, tapered over 5 days post-op. They're also given acetaminophen and hydrocodone for breakthrough pain. Patients who are more sensitive to pain, haven't responded to those medications, already take pain medications or are heavy drinkers, receive stronger doses of oxycodone, typically between 20mg and 30mg. We give patients who'll receive oxycodone after surgery a dose in pre-op and PACU to preemptively attack pain. Preemptive medication is always better than reactive medication — you want to prevent pain, not treat it.

• PONV. Controlling pain and preventing PONV are interrelated with minimally invasive surgical techniques and light sedation. Patients who undergo minimally invasive surgery typically require smaller pain medication doses, which means PONV is less of an issue. Patients who aren't nauseated or hypotensive, who aren't spaced out on pain medications, are able to walk sooner after surgery and more likely to recover quickly.

MINIMALLY INVASIVE
Why Muscle-Sparing Techniques Matter

SPARE THE QUAD Minimally invasive technique spares the quad and doesn't require knee dislocation.

There's pain, and then there are the consequences of surgery. Cutting and tearing the quadriceps muscle and dislocating the knee, trademarks of conventional knee replacement techniques, cause trauma, which results in chemical changes within the body. Blood flow increases, swelling ensues and large amounts of fluid shift. Patients who are older, unhealthy and without good reserves can develop serious issues due to those changes, which most often contribute to post-op complications. They are why patients must be monitored so closely after surgery. On the other hand, my minimally invasive technique spares the quad and doesn't require knee dislocation. Patients experience less post-op pain, less trauma, fewer chemical changes and less severe fluid shifts.

After traditional knee replacement, the quad muscle, which has been cut, doesn't function properly. Patients, however, need that muscle to ambulate. They therefore experience pain and dysfunction, resulting in incredibly long and tedious physical therapy sessions — hour-long workouts twice a day for several days — just to get on the road to recovery. Because we don't cut the quad muscle, patients' knees function normally, meaning they can get up and walk very soon after surgery. Physical therapy in recovery is brief. Patients can walk and negotiate stairs on their own, letting them meet same-day discharge criteria. In fact, patients who ambulate soon after surgery often have less pain than they experienced due to arthritis in the joint just a few hours earlier.

— Richard Berger, MD

We give patients epidural nerve blocks with propofol sedation. We focus on administering as little sedation as possible, which means patients might move slightly during surgery, making the procedure more difficult for surgeons. They have a couple of choices when that happens: Tell the anesthesia provider to administer more sedatives, which increases PONV and post-op complication risks and jeopardizes speedy recoveries and timely discharges; or tolerate the patients' movements to minimize giving intraoperative medications and to increase the likelihood of timely discharges.

To further help control PONV, we give patients 4mg prophylactic doses of ondansetron at the time of surgery. We also avoid using all IV intramuscular narcotics and don't put narcotics in epidural nerve blocks. Patients who receive narcotics are given oral doses, which can cause nausea, but the risk is much less than with IV formulas. We give patients who do become nauseated less pain medication, fluid boluses or doses of the antiemetic metoclopramide.

• DVT. Deep vein thrombosis and pulmonary emboli are always concerns and potential complications we take very seriously. Administering epidural nerve blocks instead of general anesthesia helps alleviate the risks. More importantly, patients are up and walking soon after surgery, which gets blood flowing in the legs. Lastly, we use chemical prophylaxis. Most patients take aspirin twice daily for a few weeks. We give patients with very high risk factors for DVT warfarin or low-molecular-weight heparin.

Don't assume that patients recover easily and are ready for discharge with just a few tweaks of their medications. Success in outpatient knee replacement demands constant monitoring and titration of doses based on an individual's medical history and current condition.

A highly skilled and knowledgeable surgical team is a must to make outpatient knee replacement work. So is a dedicated nurse assigned to trail patients from pre-op to PACU, ensuring they receive medications and post-op therapy at precisely the right times. Every aspect of care — epidural placements, administration of pain and PONV medications, fluid boluses, physical therapy sessions — must go off without a hitch in order for patients to meet same-day discharge criteria.

FACTS & FIGURES
The Big-Picture Benefits

TREND SETTER Richard Berger, MD, has performed approximately 5,000 outpatient joint replacement procedures since 2001.

Using techniques I developed, we began outpatient hip replacements here at Rush University Medical Center in Chicago, in 2001, on a select few healthy patients. As my technique evolved, we performed multiple cases a day on older, sicker individuals, essentially opening up the surgery to all patients. Then, in 2003, we started doing outpatient knee replacements. Since then, I've performed approximately 5,000 joint replacement procedures.

Last year, 63% of the more than 1,000 patients who underwent total hips, total knees and partial knees under my care went home the day of surgery, 35% went home the following day and 2% stayed multiple nights. More than 1 million joint replacements are performed in the United States annually and the average length of stay is almost 5 days, which equates to 5 million hospital days. Imagine how much money the healthcare system would save if more surgeons performed knee replacements that let patients go home the day of surgery or, at the very least, the day after.

— Richard Berger, MD