Foot & Ankle

End-stage renal failure and Achilles tendon rupture

Ankle instability: is rehabilitation the answer?

Chronic ankle instability is a tricky condition to treat and can be associated with significant function restriction, particularly when playing sports or walking over rough ground. The mainstays of treatment are surgery or rehabilitation and strengthening exercises. Surgery is usually seen as a last resort in these patients, as the complication burden from the surgery itself is not insignificant and, in addition, the tightening of the ankle can result in secondary degenerative changes. Although rehabilitation forms the workhorse for treatment of instability in many centres, there are a range of different options, and it is far from clear which patients will benefit from which treatments. A study team from Thessaloniki (Greece) have undertaken and published a comprehensive network meta-analysis with the aim of unpicking which of these treatments are successful and which are not.² Their study was designed to answer two different questions: which of the variety of standalone or combined nonsurgical interventions was successful in treating chronic ankle instability as measured by 1) the Cumberland Ankle Instability Tool (CAIT) and 2) treatment-related complications? In what was a comprehensively designed study, the authors conducted random-effects pairwise and network meta-analysis on the data extracted from a comprehensive search comparing various nonoperative treatments for ankle instability. The authors included all studies reporting the outcomes of patients with functional or mechanical ankle instability or recurrent ankle sprains. The authors were able to include 21 trials, which, in total, reported the outcomes of 789 chronically unstable ankles. The trials reported a variety of rehabilitation interventions, including strengthening, balance training, manual therapies, and combinations of these reported as multimodal treatment. The individual trials were assessed using the Cochrane risk of bias tool, which assessed 12 trials as having a low risk of bias. The results, unusually for meta-analysis of rehabilitation interventions, were surprisingly clear. The evidence supports four-week supervised rehabilitation program, including balance training, strengthening, and range-of-motion exercises by, on average, ten points in the CAIT. When considering just standalone interventions, the balance training was the only intervention to be better than the control (mean difference CAIT -5). There has been little doubt for some time that, even in the case of chronic ankle instability, rehabilitation protocols have a role to play as major treatment strategy. This meta-analysis underlines not only how effective these can be, but also that not all treatment strategies are equal. In the treatment of instability, a multimodal approach is clearly to be preferred.

How common is gastrocnemius tightness?

The tight gastrocnemius is a common finding in patients with foot and ankle pathology, and a link has been recognized between the tight gastrocnemius and foot and ankle pathology for many years. However, there is next to no data describing the pathological link and what proportion of patients have a significantly tight gastrocnemius. Researchers from London (UK) have reported the results of their study, which aimed to establish the exact link between the two.³ The authors set out to establish the prevalence and degree of gastrocnemius tightness in a control group of 291 patients, with a study group of 97 patients all presenting with foot and ankle pathology. This prospective study evaluated both groups of patients for gastrocnemius tightness, using the lunge test. Gastrocnemius tightness was calculated by measuring the difference in dorsiflexion of the ankle with the knee extended and flexed. There was little clinical difference between the two groups overall, with 6.0° gastrocnemius tightness in controls and 8.0° in those with foot and ankle pathology. However, there were some important differences on subgroup analysis, with patients with forefoot pathology presenting with gastrocnemius tightness of 10.3°, as opposed to 6.9° in those with other pathology. The authors sensibly conclude that, whilst previously thought to be relatively common in patients presenting with foot and ankle pathology, the majority of patients do not have gastrocnemius tightness. However, there are an important subgroup of patients with forefoot pathology that do. It is, of course, unclear from a study like this if the gastrocnemius tightness drives the forefoot pathology, or the other way around.

Charcot arthropathy and surgical treatment

One of the many sequelae of diabetes is Charcot arthropathy. Although often presenting concomitantly with diabetic foot ulcers, it is, of course, a completely different pathology. Historically, patients have been treated with accommodative casting during the inflammatory stages and then accommodative orthoses during coalescence. Whilst this is an established treatment, it does have its drawbacks. Secondary ulceration from deformity is relatively common, especially in those patients with hindfoot Charcot, and all patients report relatively poorer quality of life than those with end-stage diabetes and no Charcot arthropathy. There has, for these reasons, been a resurgence in interest in operative correction of these deformities in an attempt to address these two problems. A surgical team from Maywood, Illinois (USA) have reported their experience of operative correction of Charcot deformity with aim of resolution of any infection and limb salvage, as well as improving quality of life as measured by the Short Musculoskeletal Functional Assessment (SMFA).⁴ The authors report the outcomes of 25 patients undergoing surgical correction of midfoot Charcot arthropathy. All of their patients were unable to achieve a plantar grade foot, and their results were reported out to a year following treatment. Overall, they were able to achieve improvements in the SFMA scale. On average, patients reported 11.5-point improvement in the functional index and a 12.4-point decrease in the bother index. These authors report a successful operative reconstruction of mid-tarsal Charcot foot arthropathy; in their experience, these patients operated for midfoot arthropathy with an improved quality of life at a year following surgery.

Early reports of a new fixed-bearing ankle arthroplasty

The Infinity Ankle Replacement is a new fixed-bearing total ankle arthroplasty. Like many new implants, there is little literature published surrounding its use. In a retrospective review of 64 consecutive patients, a study team in New York, New York (USA) report the complications, reoperations, radiographic, and clinical outcomes of the Infinity.⁵ The series had an average follow-up of just over two years and the authors undertook a review of medical records and radiographs. The authors established preoperative and postoperative radiographs for alignment, component position, and evidence of loosening or subsidence. Clinical outcomes were reported as part of a patient-reported outcomes measure, the Foot and Ankle Outcome Score (FAOS). The overall survival of the implants at two years was a not-so-impressive 95.3%. In common with many series, the authors also reported a relatively high rate of complications, with 14 ankles (21.8%) suffering a total of 17 complications, requiring 12 reoperations. Subsidence of the talar implant was the cause of all revision surgery, which was required in three ankles. The tibiotalar coronal deformity was significantly improved after surgery and maintained during the follow-up period. There was a high rate of early radiographic signs visible around the tibial component; by the two-year follow-up, 20 ankles (31%) had radiolucencies visible. The picture was not all bleak, however, and clinical outcome scores were significantly improved on the FAOS score. There was a significant improvement in all components, including 39.0 to 83.3 for pain, 34.0 to 65.2 for symptoms, 52.3 to 87.5 for activities of daily living, and 15.7 to 64.2 for quality of life. The authors reach the reasonable conclusion that the majority of complications were minor. However, there was a common theme of failures and radiographic abnormalities related to the tibial implant, which definitely warrants careful longer-term follow-up series to establish if the early radiolucent lines turn into loose components.

Interference screw fixation versus Pulvertaft weave for tibialis posterior transfer

The tibialis posterior (TP) transfer is a common treatment for foot drop. By transferring the tendon, the surgeon addresses the foot drop in a dynamic way. There is little in the way of surgical options that fare better or are more widely respected. This study group from London (UK) noted, however, that the standard practice is currently immobilization of the ankle in a non-weight-bearing cast for six weeks.⁶ A potentially better regime would be early active dorsiflexion with protected weight-bearing. This would offer the potential to reduce stiffness and medical complications associated with lower-limb immobilization. The authors of this study set up a cadaveric model to establish if tendon displacement under cyclic loading differed with the Pulvertaft weave (PW) and interference screw fixation (ISF) in a cadaveric foot model. In one of the more extensive cadaveric studies we have seen here at 360, the authors undertook 24 TP tendon transfers in cadaveric feet, half with each technique (PW vs ISF into the cuboid). The cadaveric feet were then cycled 1000 times with a load range of 50 N to 150 N and then loaded to failure. Outcomes assessed were strain to failure and tendon displacements. Tendon displacement was similar in both groups; however, one specimen in the ISF group suffered early screw failure. For tendon transfer, ISF and PW techniques were comparable, with no differences in tendon displacement after cyclical loading or load to failure. However, the authors reported that there was greater variability observed in the PW group, which suggests it may be a less reliable technique.