Minimally Invasive Joint Replacement

Minimally Invasive or Traditional Total Joint?

Total joint replacement (or arthroplasty) is a procedure which involves removing part or all of the damaged joint and replacing it with artificial implants. Joint replacement surgery can improve mobility and provide significant pain relief. It may be required for advanced arthritis or as a result of an injury.

Arthritis

Arthritis can be caused by the wear and tear of routine life, injuries, avascular necrosis or other medical conditions.  Arthritis in the joint occurs when the smooth gliding surface of the joint (cartilage) wears away leaving roughened surfaces of the bones to grind against each other causing pain and stiffness.  Later on, bone spurs and deformity may develop.  Symptoms can also include swelling, instability, limping, and difficulty with climbing stairs or walking distances.  Treatment options include weight loss, medications, injection therapy with either steroids (to decrease inflammation) or a lubricant (viscosupplementations, i.e. Synvisc, Hyalgan) to improve the function of the joint, assistive devices (cane or brace), physical therapy, and surgery.  Surgical treatment options include arthroscopy (rarely used for arthritis), partial joint replacement and total joint replacement.

Traditional Joint Replacement

When nonoperative treatments have failed to provide adequate relief, joint replacement may be recommended.

Traditional total knee replacement typically involves an 8-12 inch incision over the front of the knee which allows for full visualization of the operative site.  The quadriceps tendon and muscle are split so that the procedure may be performed.  Although this tendon is repaired at the end of the surgery, it is significantly weakened resulting in pain, weakness and a prolonged rehabilitation.

Traditional total hip replacement typically involves an 10-12 inch incision on the side of the hip which allows for full visualization of the operative site.  Muscles are split or detached from the hip, the hip is dislocated and the ball and socket are replaced.  Although these muscles are repaired or reattached at the end of the surgery, they are significantly weakened resulting in pain, weakness and a prolonged rehabilitation.

Minimally Invasive (MIS) Joint Replacement Surgery

The myth is minimally invasive surgery (MIS) is defined by the length of incision, however this is not really what the benefit of MIS is all about. The important difference for the patient is the improved instrumentation and surgical techniques used to limit the disruption of muscles, ligaments, and tendons under the skin.  As a result, a less invasive surgery can help a patient recover from a joint replacement in weeks instead of months.  

MIS total knee replacement typically involves a 4-6 inch incision over the front of the knee. The quadriceps tendon and muscle are not split which results in a decrease in the amount of trauma to the knee. This results in less pain, greater strength, and quicker recovery.

MIS total hip replacement is typically performed through one or two smaller incisions.  A single MIS hip incision typically measures only 3-6 inches, depending on the size of the patient and the difficulty of the procedure.  Less muscle is split or detached than in a traditional replacement, and these are repaired at the end of the procedure to help healing and improve recovery.  

The artificial joints being used for MIS replacements are the same as those used for traditional replacement but specifically designed instruments are needed in order to prepare the socket and bone surfaces.  Implantation is the same and may involve pressed fit, screws or bone cement.  MIS replacement is more technically demanding and requires special training and considerable experience on the part of the surgeon.

Potential Benefits of MIS Joint Replacement 

• Less postoperative pain
• Less muscle damage
• Less blood loss
• Less scarring
• Better motion
• Quicker recovery
• Shorter hospital stays
• Less rehabilitation
• Quicker return to normal daily life activities

Early, active participation in physical therapy has contributed greatly to the accelerated recovery of patients undergoing less invasive joint replacement. With appropriate pain control, patients work on transferring in and out of bed, walk with a walker or cane, and climb stairs before going home. These goals can be met safely by many patients as quickly as one day, allowing for a shorter hospital stay and a quicker return to their normal routines.

After discharge from the hospital, home physical therapy is coordinated to facilitate this transition for the first two or three weeks. At the first follow up visit, 2 weeks after surgery, most patients can transition to walking with a cane, or no assist device at all.  

Am I a candidate for less invasive hip or knee replacement?

Because of advancements in instrumentation and surgical technique, a vast majority of patients can elect to undergo a small incision joint replacement. The weight or size limit is the same for any total knee or total hip replacement surgery. The size of the incision is, to some degree, driven by the size of the implants that are placed at the time of surgery.

Larger bones require larger replacement implants and longer incisions. Obese patients may require larger incisions for exposure of the joint that is being replaced, but the same care is taken to minimize the disruption of soft tissue structures at the joint level.

What are the risks or downsides of less invasive, or small incision joint replacement?

It is widely accepted that less invasive approaches to joint replacement are more difficult to perform correctly than standard approaches to hip and knee replacement. It is important to select a surgeon with appropriate training and experience performing these procedures. Specific modifications to surgical instrumentation and technique must be made to safely and reproducible perform a less invasive approach. Simply making a shorter incision without significant adaptations can result in poor surgical results and severe complications. 

Without appropriate surgical exposure or visualization, errors in alignment and sizing of components, damage to nerves and arteries, and poor soft tissue balancing can compromise the end result for the patient. It is important to talk to your surgeon about their training and experience performing minimally invasive procedures.

What are the results of less invasive joint replacements?

Currently there are no long-term studies of minimally invasive joint replacements as the techniques and instruments used to perform these surgeries have been evolving over the last ten years. The long-term benefits of these techniques have not been documented to represent an improvement over the traditional method.  The orthopaedic literature suggests patients who undergo a less invasive joint replacement enjoy a faster recovery in the first 2-4 weeks after surgery. 

Studies have documented less blood loss at the time of MIS surgery, less pain and pain medication usage, shorter hospital stays, faster return to walking with a cane or no assist device, and faster return to work. These early advantages are only significant in the first 6-12 weeks after surgery. 

Results for all total joint replacement patients

By 3 months, all joint replacement patients have achieved 90% of their ultimate recovery regardless of the approach used at the time of surgery. Long term success of a hip or knee replacement depends on the appropriate selection, sizing, and alignment of the implants, not the surgical technique used. 

Current studies of long-term results of hip and knee replacement suggest a 90-95% survivorship of the reconstructed joint at 20 year follow-up.

What are the goals of less invasive surgery?

The goal is to safely and accurately reconstruct your hip or knee while disrupting as little normal tissue around your joint as possible. This results in faster relief of pain and restoration of normal function, getting you back to life, back to work, and back to the activities that you enjoy most.

Ask your doctor if MIS is right for you.