Minimally Invasive Total Joint Arthroplasty: Where Are We Going?

The purpose of total joint arthroplasty of the hip and knee is to safely and effectively relieve pain, restore motion, and improve function. In less than three months, the vast majority of patients can return to the activities of daily living and can participate in certain sports. As a result, total joint arthroplasty has become one of the most successful and widely acclaimed procedures of the modern era.

Recently, minimally invasive surgery, which involves a smaller incision (defined as <10 cm) or multiple smaller incisions, has been introduced to both hip and knee replacement surgery1–3. The premise is to reduce the trauma of surgery while maintaining the perceived high levels of safety, efficacy, and durability of the procedure. If it is done successfully, patients can expect a shorter hospital stay, quicker recovery, faster rehabilitation, improved function, and better cosmetic appearance, which should all translate to lower costs and higher patient satisfaction.

Minimally invasive surgery is not a new concept. The minimally invasive direct coronary artery bypass surgery (MIDCAB) was pioneered by cardiac surgeons in the early 1990s4. With use of tiny incisions scattered around the chest, cardiac revascularization was accomplished without the need for sternotomy and the pump. The results were truly impressive. The length of stay was reduced by two days, and the costs were substantially lowered. Promotional marketing of this new surgery was done with great fanfare.

However, almost ten years after the introduction of the minimally invasive direct coronary artery bypass procedure, only about 25% of cardiac surgeons use this technique5. Wound infection, myocardial infarction, atrial fibrillation, stroke, and mortality continue to be problems. Properly done prospective, comparative studies are lacking. The safety, efficacy, and durability of the procedure have not been demonstrated conclusively6. Over time, the minimally invasive direct coronary artery bypass procedure has evolved and has now become more widely accepted with sternotomy and without the pump7.

This raises a question. Will we follow the same path, or will we learn from the cardiac experience and do the appropriate prospective controlled studies, which will, in turn, give us the knowledge to provide the best care for our patients?

Minimally invasive surgery for total joint arthroplasty should not be used to benefit an individual surgeon, a manufacturing company, or a hospital. Unfortunately, minimally invasive surgery seems to have become a marketing tool for these groups.

To become accepted by and acceptable to the majority of orthopaedic surgeons, minimally invasive surgery must be subjected to properly designed and rigorously controlled studies to test its safety, efficacy, and durability. Before minimally invasive surgery can be adopted as a standard of care, statistical data from multiple centers must be collected, analyzed, and subjected to peer review.

The concept of minimally invasive surgery is a good one. Technological advances, including new surgical procedures, encourage better patient care. Minimizing tissue trauma is desirable, but not at the expense of safety, efficacy, durability, and overall patient satisfaction. The precision and position of component implantation cannot be compromised. To gain widespread acceptance, any new procedure must meet these stringent criteria.

Total joint arthroplasty has many complications; some of the more serious ones are irreversible. The only good solution for many of these poor outcomes is prevention through technical excellence, which may be more difficult with minimally invasive surgery.

Although minimally invasive surgery may appeal to younger, more active patients (those who are between thirty and sixty years old), their primary concern should be function and durability. Moreover, minimally invasive surgery may be contraindicated in this subgroup since many of them have protrusio deformities, fibrous or osseous ankylosis, or a hip scarred by previous surgery or they are obese, thereby making minimally invasive surgery technically more difficult.

If its safety and efficacy can be established, minimally invasive surgery, like minimally invasive direct coronary artery bypass surgery, may become the procedure of choice for elderly or high-risk patients4.

Until we have sufficient scientific evidence to support its universality, minimally invasive surgery should be performed only by surgeons who can evaluate the procedure and thus compare it with the conventional technique. Unless the safety and efficacy of the procedure are validated scientifically, no promotional or marketing support of minimally invasive surgery should be condoned. Otherwise, as orthopaedists, we will have failed in our duty to provide our patients with the best possible care.