Total ankles and wound complications

The curse of the foot and ankle surgeon is the soft tissues. The poorest outcomes from surgery are undoubtedly dictated by the soft tissues. In the foot and ankle, this effect is magnified and major wound breakdown following total ankle arthroplasty is a genuine problem. A truism is that the best treatment for soft-tissue complications is to avoid them at all costs. However, as this group from Durham, North Carolina (USA) point out, little is known about the potential intra-operative factors that may contribute to the development of wound breakdown.² The authors set out to establish whether the relative tissue hypoxia associated with tourniquet use is responsible for poor wound healing or if, in fact, other factors are at play. To answer this question, the authors prospectively collected data on 762 primary total ankle arthroplasties, of which a subset of 26 patients (3.4%) required operative intervention for major wound complications. All of these ankle arthroplasties were performed at the same institution by specialist foot and ankle surgeons. An anterior incision and standardised approach was routinely used, with interrupted vertical mattress nylon sutures for skin. The authors’ routine practice was to treat wound breakdown with a vacuum-assisted closure (VAC) dressing in superficial cases where there were no exposed tendon, neurovascular structures or implant material. Any patients with more significant soft-tissue defects underwent surgical reconstruction. In this cohort of 26 patients, 49 individual operative procedures were performed. With regard to plastics reconstructions, 18 patients had flaps and eight had skin grafts. In terms of picking out the aetiology when compared with the control group, patients with major wound complications had a significantly longer mean surgical time which was also matched by a statistically significant increase in tourniquet time in that group. There were eight patients who developed a significant deep space infection out of the 26 (30.8%). These cases required multiple returns to theatre for drainage and exchange of components. Two of those eventually required below-knee amputation. We are, in general, poor at reporting our own complications. In particular, many surgeons shy away from sharing their problems, when in fact this is precisely where we can learn the most. We applaud these authors for their frank and honest account of deep wound complications following ankle arthroplasty. From the data presented in this large series, it is clear that the outcomes of major wound complications after total ankle arthroplasty are poor with a significant surgical burden, and some even resulting in amputation in a small number of those cases. Although there was no direct association found with the tourniquet time, the trend is something we should all be mindful of; longer surgery with longer tourniquet times is clearly not good for your patient’s soft tissues.

Biomechanics, gait and ankle replacements

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The problem with ankle replacement is not actually the replacements, which are limited somewhat by longevity, complications and failure to restore function in its entirety. Rather, we would argue, here at 360, that the problems with satisfaction, from both surgeons and patients, with ankle arthroplasty is that the alternative, an ankle fusion, is really quite comparable. There are two basic alternatives in design philosophy available within the world of ankle arthroplasty – fixed and mobile bearing. One of the factors continuing to push forwards evolution in ankle arthroplasty is the wish to restore more normal biomechanics. There are few patients who would report that their ankle feels ‘normal’ following an arthroplasty, and this is, to a certain extent, due to the altered biomechanics of gait. These authors from Durham, North Carolina (USA) have set out to determine whether these two competing philosophies of ankle arthroplasty design have any effects on gait mechanics in a randomised controlled trial of ankle arthroplasties.⁵ Their study was designed to establish pain scores and gait mechanics at one year following surgery. The authors were able to recruit just 40 patients to their study from 144 eligible patients during the study period, and one has to be wary of the potential issues with selection bias here. All patients included in the study had isolated osteoarthritis of a single ankle, were independently mobile, and weighed less than 250 pounds with minimal pre-operative sagittal and coronal plane deformities. Twenty patients were randomly assigned to each bearing type, and surgical details, other than mobility of the bearing, were identical. Outcomes were assessed as both gait analysis including the usual gamut of outcomes, and 33 patients were included in the final analysis. Perhaps unsurprisingly, this small trial did not reveal any significant problems. The authors, however, did usefully undertake some power and effect size calculations, and determined that the observed effect sizes required a trial of between 66 for the largest observed effect (propulsive vertical ground reaction force) and 2336 for the smallest effect (walking speed).

Platelet-rich plasma in ankle osteoarthritis

Like a bad penny, platelet-rich plasma (PRP) just won’t go away. Despite the wide range of studies demonstrating no efficacy, investigators continue to evaluate the potential effects of PRP on a whole variety of indications. Orthopaedic surgeons in Chiba (Japan) identified another diagnosis in which PRP hasn’t been tested – treatment for osteoarthritis (OA) of the ankle.⁶ The authors report a small case series of 20 patients, all treated with injection of PRP for varus-type ankle OA. Three injections of 2 mL PRP were administered under ultrasonographic guidance. The efficacy was established using the Visual Analogue Scale (VAS), the Japanese Society for Surgery of the Foot (JSSF) ankle/hindfoot scale, and the Self-Administered Foot Evaluation Questionnaire (SAFE-Q). The authors report a marked benefit with the injections, with significantly better outcomes at four, 12 and 24 months post injection. There were no serious adverse events, and the authors conclude that PRP treatment is “safe, effective and may be an option for ankle osteoarthritis”. However, although there was an improvement and no complications, there was no comparator group. We are perhaps less enthusiastic about PRP, given this series, than the originators are. Clearly, until there is a comparative outcome series there is little or no evidence to support this treatment.