NORTH TEXAS TOTAL ANKLE

Ankle Arthritis

Ankle arthritis is increasingly recognized as a major source of morbidity, impacting younger adults in their most societally and monetarily productive years (age 55 for fusions and 63 for replacements ). This cohort of 55-year-olds likely have 10 more productive work years prior to retirement as compared to hip or knee arthritis patients who are already in their retirement years (65 in total hip arthroplasty and 66 in total knee arthroplasty ). Although less prevalent than in the hip or knee,  ankle arthritis can lead to a greater societal impact by detrimentally affecting vocational abilities and resulting in loss of employment productivity, because of the younger age of onset. 

Comparing Arthrodesis to TAA

An early systematic review demonstrated similar outcomes between TAA and ankle arthrodesis.  However, the data then were not of high quality and the authors were unable to make strong conclusions. A paper by the COFAS group in 2014 reviewed 321 ankle arthritis cases treated with fusion or TAA with a mean follow-up of 5.5 years and showed similar outcome scores between the 2 procedures. However, TAA resulted in higher complication rate (7% arthrodesis vs 19% TAA) and reoperation rate (7% arthrodesis vs 17% TAA).  Newer literature demonstrated increased complications and reoperations with TAA compared with arthrodesis, but both achieved similar clinical outcomes.  Another study showed that TAA patients have improved motion, pain control, and perceived outcomes postoperatively.  However, both have poorer outcomes if swelling is significant.  Level I evidence for TAA compared with fusion is still lacking, and hence the justification for the in-progress multicenter randomized trial of total ankle replacement vs arthrodesis (TARVA) based in the United Kingdom.  Joint-Preservation Strategies

Aside from arthrodesis and TAA, there exists other recognized but less common surgical treatments. Joint preservation strategies are ideal for the younger population and have been of interest in the hip, knee, and ankle as an alternative to arthroplasty or arthrodesis. In the ankle, these include simple debridement, realignment osteotomies, distraction arthroplasty, and other less common procedures.

Joint debridement 

The purpose of debridement in ankle arthritis is primarily removal of marginal impinging osteophytes to relieve both the impingement causing pain and associated stiffness in cases of mild arthritis. This treatment can be performed via open surgical approaches, but is frequently done arthroscopically with improved results.  The technique involves performing a diagnostic arthroscopy, identifying the impinging osteophytes, and removal with burrs, curettes, and rongeurs. Impingement can be a result of malalignment, and in these cases, consideration should be given to correction of this malalignment in addition to addressing the osteophytes, such as in planovalgus deformities. Debridement is not appropriate for moderate or severe cases of arthritis; by removing osteophytes and increasing range of motion through arthritic articular surfaces, this can cause increased pain and poor outcomes. 

Realignment osteotomies 

In patients with ankle arthritis affecting only a portion of the joint surface, realignment of the mechanical axis such that weight-bearing shifts to the preserved portion of the joint can be performed with osteotomies. The ideal candidate is a younger, active individual who does not want a joint-sacrificing procedure such as fusion or arthroplasty. Conceptually, this is akin to the high tibial osteotomy for varus knee medial osteoarthritis to preferentially load a preserved lateral compartment. Physical examination findings can suggest a role for realignment prior to any imaging. For example, a planovalgus deformity with tenderness in the lateral gutter and sinus tarsi is consistent with a valgus pattern of ankle arthritis and possible preservation of the medial side of the joint. If this diagnosis is confirmed on imaging, realignment surgery may be possible instead of ankle fusion or replacement. The obvious prerequisite is eccentric wear with some remaining articular cartilage to load through after realignment, ideally 50% or more.  In cases of underlying foot deformity and asymmetrical ankle arthritis, such as a planovalgus foot with primarily lateral ankle arthritis or cavovarus foot with primarily medial ankle arthritis, correction of the foot deformity may also realign the mechanical axis enough to relieve pain. The commonly reported supramalleolar osteotomy is a powerful technique that affords a higher degree of angular correction for this purpose as it occurs more proximally and can be done in combination with foot deformity correction. The end goal is to restore neutral talar alignment within the mortise both in the sagittal and coronal planes, and slight overcorrection is sometimes advocated.  In varus ankle arthritis, a medial opening wedge osteotomy with bone graft is typically done, although a lateral closing wedge osteotomy is also an option. Similarly, valgus ankle arthritis can be treated with medial closing wedge supramalleolar osteotomies or lateral opening wedge osteotomies. In either case, fixation is usually with plates and screws but external fixation is also an option, and deformity correction can be done with adjustable ring fixator systems. Angular corrections over 10 degrees may require concomitant fibular osteotomies, and large opening wedge osteotomies will cause lengthening. One must be cautious of lengthening to the surrounding soft tissues such as tendons and nerves, and dome osteotomies should be considered instead to minimize this. Many series have been published with good results.  This technique has potential use with appropriate patient selection, but current literature is still insufficient to recommend broadly. 

Distraction arthroplasty 

This technique involves the application of a ring external fixator to the ankle to apply distraction across the tibiotalar joint to unload it, relieving pain and possibly delay or reverse osteoarthritis.  The frame can be fixed but is usually hinged at the ankle to allow motion, and the patient is permitted to weight bear.  The ideal candidate is one who is not suitable for other joint-preservation techniques, but does not want joint-sacrificing surgery such as fusion or arthroplasty. Indications and technique are well described,  but the mechanism of action is still unclear, results confounded by concomitant procedures, and scientific evidence to support its general use in ankle arthritis is insufficient, according to several reviews.

Other procedures 

There has been some interest in other even less common procedures, such as interpositional arthroplasty and osteochondral allograft transplantation, but current evidence is lacking to recommend them. 

Although less common than that of the hip or knee, ankle arthritis is a significant disease of variable etiology affecting a younger working-age group with an increasing number of reliable surgical and nonsurgical treatments. Proper treatment of these conditions depends on meticulous patient evaluation both of the ankle pathology as well as systemic medical issues and lower limb alignment. The invasive nature of surgical treatments warrant exhausting nonoperative measures first and delaying the index procedure. However, failure of nonsurgical treatments would merit surgery in an appropriate candidate. Arthroscopic ankle arthrodesis, although still less commonly performed in the United States compared with open techniques, can be the superior fusion technique in experienced hands in patients with limited coronal plane deformity because of its inherent minimally invasive nature. In the future, more durable TARs may allow usage in younger patients in addition to the gold standard of ankle arthrodesis for end-stage ankle arthritis. Better understanding of ankle anatomy and biomechanics may increase the prevalence of joint-preservation techniques such as supramalleolar osteotomy in this unique population.