Technology and technique advancements over the past decade have seen two big game changers – the rise of minimally invasive foot surgery and improved total ankle replacement.
Minimally invasive (MI) foot and ankle surgery has revolutionised my practice in recent years, particularly for forefoot deformities.
Previously, the mainstay of bunion (hallux valgus) and toe deformity correction surgery involved open approaches, often with significant stripping of the periosteal blood supply to bones and more risk of soft tissue damage. Bigger cuts result in more swelling and scar tissue, which can create stiffness, wound healing issues and pain.
Respect for the soft tissues in a foot is always paramount given the relative paucity of soft-tissue coverage over the bones and the proximity of neurovascular structures, no matter which part of the foot is being operated on.
MI cutting burrs under x-ray guidance allows us to address a range of foot problems using small keyhole incisions. This includes bunions, bunionettes (the bunion equivalent at the fifth toe), hammer/claw toes, and metatarsal deformities. We can remove bone spurs around arthritic joints (such as with big toe arthritis) and undertake calcaneal slide osteotomies (often done as part of a flatfoot or high-arched foot procedure).
In diabetics with peripheral neuropathy, MI techniques now allow removal of bony prominences causing pressure areas or ulcers through tiny incisions, diminishing wound healing problems and infection in these high-risk feet. We can even do some major deformity corrections in a Charcot foot using only small incisions along with percutaneous fixation.
Minimally invasive foot surgery usually results in less swelling, pain, scarring, and wound healing issues, as well as providing better cosmesis. MI techniques compared with open techniques have also been found to better correct forefoot deformities, particularly bunions and hammer toes.
Total ankle replacement
Ankle joint arthritis is significantly disabling and has similar impacts on quality of life and pain compared with hip and knee arthritis. Most ankle arthritis is post-traumatic as opposed to osteoarthritis in the hip and knee. This results in ankle arthritis patients being on average younger and higher demand, leading to significantly increased forces going through a much smaller joint.
For over 50 years, ankle fusion has been the mainstay of surgical treatment for end-stage ankle arthritis. While total ankle replacement (TAR) was first performed in the 1970s, early generations of ankle replacements had high failure rates, leaving some surgeons to wonder whether it was even possible to replace the ankle joint with the same success that we see in the hip, knee, and shoulder.
In the last decade, big advances have been made in the implant technology and instrumentation for TAR, along with a deeper understanding of foot biomechanics and why earlier generations of implants failed.
One of the current fourth-generation ankle replacement systems allows patients to undergo a pre-operative CT scan which is used to create custom 3D-printed patient-specific cutting guides, allowing the TAR to be implanted with increased accuracy, while also reducing surgical time. Stemmed options are available, which can be used for better implant fixation in poor quality bone.
Perhaps most importantly, revision implant options are better developed, giving us the ability to keep a patient’s ankle joint moving with another replacement in the case of failure, as opposed to converting to a challenging hindfoot fusion or even below knee amputation.
A better understanding of foot biomechanics and why previous TAR designs failed is also leading to improved longevity. I half joke with patients that my hip and knee colleagues have it easy, with one bone above and one bone below their replacements – we have to balance two bones above, and 24 bones below! We now know that replacing an ankle without addressing deformity of the foot below the ankle is a recipe for failure – a plantigrade foot under an ankle replacement is a must for a long-term good outcome.
Key messages
- Minimally invasive foot surgery techniques offer the ability to correct a range of deformities through keyhole incisions
- Total ankle replacement outcomes and survivorship are significantly improving with new implant systems and better instrumentation including 3D printing technology
- Studies now show similar pain relief with ankle replacement vs fusion, with TAR providing the advantage of a more normal gait cycle and foot biomechanics.
Author competing interests – nil