Minimally invasive foot and ankle surgery: when is it appropriate?

Minimally invasive surgery (MIS) has become increasingly common in all areas of orthopaedics, but it’s still early days for its use in feet and ankle surgery. A Mediclinic expert explains why its efficacy must be assessed on a case-by-case basis.

Dr Michael Abramson, an orthopaedic surgeon at Mediclinic Cape Town, has performed multiple innovative MIS procedures during his career, more than 10 of these since assuming a full-time position at Mediclinic Cape Town in January this year. These procedures include multiple hallux valgus (bunion) surgeries as well as calcaneal slides that change the alignment of the calcaneus (heel bone). He has also performed a flat foot reconstruction with a burr – a popular MIS instrument used to shape bones.  

But patients must be aware of what risks and benefits MIS offers, Dr Abramson cautions.

Why MIS?

“Wound issues of the foot and ankle are terribly difficult to fix,” he says. “That’s because the blood supply to your feet is not as good as it is to higher parts of your body.” The reason for this is that feet are further away from the heart. The greater the blood supply it receives, the more easily a wound will heal. As a result, a wound problem in the ankle, foot, or toe is difficult to treat. The fact that wound complications are less likely with MIS has fuelled Dr Abramson’s passion for it.

MIS also results in smaller scars, which is a big cosmetic drawcard for patients. It also means slightly less pain, slightly less swelling, and the ability to get back on your feet a little bit quicker, which can aid recovery.

Dr Abramson, however, points to the lack of MIS training in South Africa in foot and ankle surgery. “MIS is not really taught at a resident or registrar level anywhere in this country as it's expensive to do and the implants are not available in state,” he explains. But he did do an 18-month fellowship with Professor Graham McCollum, head of foot and ankle at Groote Schuur Hospital. Dr Abramson has brought this experience to Mediclinic Cape Town and plans to further his training in Australia where MIS techniques are becoming standard.

Understanding MIS risks

Despite his interest in MIS, Dr Abramson stresses the need to assess its risks as well as its benefits. He also points to the lack of long-running research around relatively new MIS techniques in foot and ankle. Meanwhile, more than 50 years of data exists for open surgery, so it remains the most common approach.

While wound complications are minimised with MIS, there are still risks, he cautions. “Even though the scar is smaller with MIS, the surgery is not smaller. You’re still cutting a bone, and you can’t make a bone heal quicker or avoid swelling. Also, while potential complications may be different with MIS, they’re not fewer in number.”

For example, there's a higher chance of nerve complications with MIS than with open surgery. “During an open procedure you can see a nerve that may be nearby,” Dr Abramson explains. “You can dissect it or make sure your cuts are nowhere near the nerve. This is not the case with MIS. Here, you may have an idea of where the nerve is, but you can’t see it with the naked eye. You're doing a blind surgery, relying on X-rays and on standard anatomy, but all anatomy is different.”

When to do MIS

“MIS isn’t appropriate for every patient,” says Dr Abramson. “Even if you have the skills for MIS, it's only effective if you pick the right patient for the right surgery. There's still a learning curve, not just to the technical aspect of doing the MIS but to determining who should get it and why and ensuring they’re aware of possible complications.

“If there’s a surgery with years of data behind it and a 95% success rate, for example, that’s a winning formula and there’s no reason to change the approach.” When operating on lateral ligaments, for example, he prefers to stick to open surgery.

“Toe surgery is slightly different, though,” he says. “The complication rate for open hallux valgus surgeries is 30% worldwide.” Hallux valgus refers to bunions – a widespread misalignment of the big toes, which can lead to painful arthritis of the big toe. “If there's a 30% complication rate with open surgery here, maybe there's a better way to do it,” Dr Abramson says, “and MIS – which has great new technology – may be the answer.”

Regardless, doctors must still ensure the patient is an appropriate MIS candidate. For example, older patients with very soft tissue and limited blood supply may benefit from the smaller incisions that MIS offers. However, if the angle of the hallux valgus repair is too severe, MIS is not recommended. If it’s already arthritic, simply shifting the bone will not help either, in which case an open fusion is needed.