BioMechanics

February 2003

 Cover Story

Anticipating amputation: The case for communication

Forward-thinking surgeons are seeking input from prosthetists and other practitioners in developing techniques that will improve functional outcomes in amputees.

By: Charles Kupperman

Surgical techniques that fail to anticipate an amputee's functional needs are in part to blame for a disappointing lack of improvement in prosthetic outcomes over the last four decades. But a new generation of surgeons is working to reverse this trend.

Prosthetic outcomes for amputees haven't improved over the past 40 years, according to a new study by a team from the Rochester, MN-based Mayo Clinic. Not only that, but rates of amputation appear primed to double by 2030, the researchers warned. In their study, published in the October issue of the Archives of Physical Medicine and Rehabilitation, they predict an increase in the rates of amputation from 28,000 to 58,000 per year over the next 27 years.

"This is kind of a depressing thing for me," said Karen Andrews, MD, one of the study's principal authors. Andrews, chair of amputee rehabilitation, had expected the study to conclude that advances in prosthetic technology had led to a significant improvement in outcomes.

Before her team compiled its research, Andrews had believed that 80% of amputees ended up using prosthetic devices successfully. Instead, the proportion was more like 32.4% total, or 47% for below-the-knee amputees and 13% for above-the-knee amputees.

These percentages didn't differ significantly between the groups of patients whose amputations took place in two different time periods, from 1956 to 1973 and from 1974 to 1995. The study defined a successful prosthetic rehabilitation as one in which the patient achieved discharge from inpatient and outpatient physical therapy with a definitive prosthesis, which patients receive after wearing a temporary "preparatory prosthesis" for six months to a year.

Andrews has a few theories to explain the disappointing data. Many patients with vascular disease serious enough to require amputation probably have cardiac problems in addition to arterial problems in their extremities, which may reduce their ability to use a prosthesis. And the data may be less rosy than the existing literature because Andrews' team studied the whole amputee population of Olmstead County, MN, instead of merely looking at patients referred to a particular amputee clinic, and thus avoided the bias that comes from looking at a referral population, she said.

Another possible explanation for the dismal lack of improvement since 1956: surgical techniques haven't kept pace with improving prosthetic technology.

"Amputation techniques have changed little over the years and are usually performed by the most junior member of the surgical team," according to a study led by John Ertl, MD, of Hinsdale, IL. "In contrast, the prosthetic industry has made significant advances in accommodating the amputated extremity, at times attempting to improve on less than optimal surgical results," continued the report, which was presented at the annual meeting of the American Orthotic & Prosthetic Association in mid-October.

The prosthetic solution

That dismal view resonates with many prosthetists, who say that surgical mistakes can make their jobs much more difficult.

"We all, as prosthetists, see a lot of very bad amputations," said Bill Copeland, CP, with Copeland Prosthetics & Orthotics in Tampa.

Surgeons sometimes fail to properly attach muscles to bones, or leave the bones too sharp at the distal ends instead of rounding them off, Copeland said. Or they'll fail to retract nerves enough.

A surgeon needs to find a number of nerves during an amputation and cut them back so they're not in high-stress areas, said orthopedic surgeon Lew Schon, MD, chief of foot and ankle services at with Union Memorial Hospital in Baltimore.

"Occasionally the surgeon will not address one nerve or won't address it adequately," Schon said.

Surgeons don't have much control over some of these problems, Copeland conceded. For example, surgeons can't always control the length of the residual limb.

But surgeons often view amputation as a sign of their failure to save a patient's limb, say many prosthetists and some surgeons. And patients whose amputations fail to resolve problems can require revision surgery later.

There's no question that correct surgical procedures can drastically reduce the need for revisions, said Jan Stokosa, CP, with the Stokosa Prosthetic Clinic in Okemos, MI. Often, revision surgery is a never-ending battle to reduce or eliminate problems with bones, nerves, muscles, blood vessels, or scar tissue caused by "conventional" amputation techniques, he said.

There are two major reasons an amputee may require revision surgery within the first six months after an amputation, Schon said. One reason is infections, which usually can be controlled without additional surgery in the absence of complicating factors. The other reason is falls, which a successful prosthetic rehabilitation can curtail. Falls can lead to soft tissue trauma, which may reopen a wound or create a new wound, Schon said.

Schon and a team of researchers found that 19 patients who used an immediate postoperative prosthesis (IPOP) for transtibial amputations required no surgical revisions, whereas 11 patients in a control group using soft dressings required one or more revisions each, in a study published in the June issue of Foot and Ankle International. Not only did IPOP patients fall less often, but they maintained their tissues in a healthier fashion and they were able to become active sooner, said Schon. This study argued for the use of IPOPs, but also showed the benefit of successful prosthetic rehabilitation in preventing revisions.

Patients will have fewer complications if they use any prosthetic system postoperatively and receive early training in its use, Schon said. A patient will be more physically skilled and therefore less likely to have missteps or lose his or her balance, and the prosthesis will protect the limb.

There are also several reasons for revisions on a longer term basis, according to Schon. These can include pain from neuromas or bony issues, such as fibular instabilities. The overgrowth of one bone with a spur also can require a revision, as can bones that are contoured.

Also, patients can require revisions if their soft tissues don't grow enough of a pad on the distal end of the residuum, Schon said.

Patients with traumatic injuries may need a series of additional surgeries to reconstruct the layering of the various tissues, Stokosa said. And severe damage to nerves, muscles, or soft tissues may require additional corrective surgery.

In the past, the prosthetic industry didn't have much to offer, said Jan Ertl, MD, chief of orthopedic trauma with Kaiser Permanente in Sacramento, CA, and the son of John Ertl.

"You could put a peg leg on and that was it," Ertl said.

But over time, the prosthetics industry began compensating for lackluster surgeries, and eventually came up with devices that would allow patients to walk, run, and carry on a more normal life, he said.

Flexible plastics have represented a major advance in prosthetic technology, Copeland said, himself an amputee who would never consider going back to the old hard sockets. Materials such as silicone give flexibility and adjustability to the socket itself. Also, prosthetic limbs have better foot and knee components than in the past, allowing them to bear more weight. Finally, prosthetists have learned better fitting techniques as their understanding of anatomy and the importance of a stable gait have improved, Copeland said.

Winning surgical techniques

John and Jan Ertls' claim that surgical techniques haven't improved since the Korean War is an overstatement, Andrews said. Surgeons are less likely to view amputation as a failure of the limb revascularization process, and more likely to view it as part of helping a patient get on with his or her life. And many surgeons are seeing it as more reconstructive, she said.

Surgeons must see an amputation not as a salvage operation, but as the beginning of a patient's new life, said Robert Klapper, MD, clinical chief of orthopedic surgery at Cedars-Sinai Medical Center in Los Angeles.

They must spend as much time as necessary to give the bony residuum a decent muscle covering and minimize the patient's pain, he said. In transtibial amputations, it's important to bevel the edge of the tibia cut to round it off, and to recess the cut of the fibia, so it's bounded and recessed deep in the muscle.

"It's very important to keep as much of a posterior muscle flap as possible so you can swing it forward and have a beautiful pad," Klapper said.

The principles are similar for both transfemoral and transtibial amputations: bringing together posterior and anterior muscles and repairing the muscle so it won't retract or recede later.

"It's similar to the teaching in orthopedics that when we do a knee replacement, it's not a bone operation as much as it is a soft-tissue-and-ligament balancing and reconstruction operation," Klapper said.

Hip disarticulation surgery, less common than transtibial or transfemoral amputations, requires a similar muscle padding, he said-but each hip disarticualtion patient requires individual attention because the cut is higher in the pelvic girdle.

A through-the-knee amputation is usually a life-saving procedure and the surgeon doesn't expect the patient to ambulate with a prosthesis, Klapper noted. The main reason to opt for a through-the-knee amputation is because it's a quick procedure that suits patients who are too frail to be anesthetised for long, he said.

For upper extremity amputations, Klapper said it's important not to rely on skin to create a successful myodesis. As in the lower limbs, he said, it's important to use muscles to create a cushion.

Third-generation wizardry

To the basics that Klapper espouses, some surgeons are adding a new look at a post-World War I intervention technique. Janos Ertl, father of John and grandfather of Jan, pioneered the bone-bridge technique in Hungary in the 1920s, and the recent AOPA paper, co-authored by the three Ertls and Stokosa, demonstrated its long-term effectiveness.

The paper described a transtibial bone bridge in two steps: suturing the lateral tibial flap to the medial fibular flap to create a superior barrier, and suturing the medial tibial flap to the lateral fibular flap to create an inferior barrier. Osteogenesis creates a bony bridge, forms a synostosis, and stabilizes the fibula.

For transfemoral amputees, the Ertl technique involves removing all exostosis and incising the periosteum from its anterior aspect to posterior. The surgeon uses a 45º angled chisel to elevate medial and lateral osteoperiostial flaps, rotates the chisel 180º to lift and maintain the bony attachments, then transsects the femur at the flaps' level. Finally, the surgeon sutures the medial and lateral flaps over the end of the open medullary canal.

Before surgery, the patients in the study suffered from what the authors called "the inactive residual extremity syndrome," or a residual limb that serves as a passive attachment for a prosthesis due to pain, bone and muscle atrophy, swelling, weakness, instability, or poor prosthetic fit with cutaneous breakdown.

When the researchers followed up with the patients an average of nine years after reconstruction, they showed significant improvement. One hundred thirty eight out of 143 transtibial reconstruction patients and 67 out of 72 transfemoral patients scored as good or excellent on a 30-point scale the researchers devised to measure residual extremity pain, function, swelling with use, hours of prosthetic wear, subjective stability, and overall patient satisfaction.

Most patients showed a significant reduction in pain and decreased swelling, and all but one patient showed improvement in functional capabilities and subjective stability. Transtibial reconstruction patients wore their prostheses an average of 14.5 hours per day after the operations, compared with 9.15 hours a day before the operations. Transfemoral patients increased their prosthesis wear from 8.2 hours a day to 13.7 hours a day.

"The Ertl procedure improves the stability of the limb because you have a two-boned leg working like a two-boned leg, with stresses being transferred between the tibia and fibia," Schon said. "Without the bridge, you have stresses on the tibia or fibia alone."

In both BK and AK amputees, the technique increases the area of potential weight-bearing and distributes loads more effectively, he said.

Schon took part in a study led by David Navid, DO, on using a surgical modification of the Ertl procedure for transtibial amputations. In this version, surgeons used a segment of the fibula instead of an osteoperiosteal flap to create a bone bridge, according to the study, presented in July at the summer meeting of the American Orthopaedic Foot and Ankle Society. A dozen patients who received the modified bridge reported favorable outcomes.

The patients' weight-bearing surface area increased threefold and patients could put up to 10 times more weight on the residuum than before the bridge, Schon said. The researchers found no statistically significant difference in self-reported function between bridge and nonbridge patients, but found a dramatic improvement in bridge patients compared to their prebridge answers.

The Ertl technique is often described as synonymous with the "bone bridge," Ertl said, but in fact its objectives are more complex. Because the leg muscle retracts like a rubber band when cut, the Ertl technique focuses on creating a better foundation for the muscle padding, to establish a length-tension relationship in the muscle. The bone bridge is just part of that process, he said.

While Ertl agreed with others who called amputations a form of plastic surgery, he said the end goal wasn't purely an aesthetic one. Instead, he prefers the term "functional asthetics"-creating a limb that is beautiful in its ability to improve prosthetic outcomes.

Charles Kupperman is a freelance writer based in San Francisco.

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Prosthetist involvement can begin in the OR

It's important for surgeons to include prosthetists in amputations as early in the process as possible, said Robert Klapper, MD. He usually has the prosthetist come into the operating room to put on the initial postoperative dressing, so he or she can see the wound.

"It gives them such an advantage to be part of the team from the beginning," Klapper said.

That's not always standard operating procedure, according to prosthetists. Some surgeons call in the prosthetist before surgery, and some call a month later, according to Sander Nassan, CPO, with Prosthetic and Orthotic Associates in Scottsdale, AZ. Nassan prefers to sit down with the patient before the operation and offer assurances that he'll be there to help.

"Sometimes you don't even know the amputation's been done until the patient rolls in with a scrip and a big fluffy dressing on the end of their limb," Nassan said.

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