Outcome after protected full weightbearing treatment in an orthopedic device in diabetic neuropathic arthropathy (Charcot arthropathy): a comparison of unilaterally and bilaterally affected patients
The outcome of non-operative treatment in 90 patients (101 ft) diagnosed with CN was assessed at a mean follow-up of 48 months (range 1–208 months). The average age of patients in our investigation was 60.7 (±10.6) years, which corresponds to previously published studies [27–29].
Treatment in an orthopedic device, such as a TCC to minimize mechanical forces on the bone, achieve a plantigrade, stable foot and prevent recurrent ulceration, is considered to be an important strategy in acute CN [6, 24, 27, 30–34]. Yet, there is a wide range of recommendations concerning initial treatment. Some authors suggest non-weightbearing treatment during the first months to stop progression of deformity [27, 29, 34, 35]. In particular, they suggest that weightbearing should be prevented during the inflammation stage, to “cool down the foot” because of the risk that the unstable foot will continue to fracture [10, 35]. Frykberg et al recommended a non-weightbearing period of 8–12 weeks to avoid trauma to the affected foot [34]. Other investigators allowed weightbearing when the foot was placed in a cushioned device [10, 36–38]. De Souza et al showed that protected weightbearing in a TCC does not initiate new foot ulcers in the treatment of a Charcot foot [10]. Weightbearing does not appear to negatively affect the outcome in treatment of acute CN, as long as the foot is protected by a professionally manufactured TCC. Initial treatment in our institution consisted of a custom-made, properly cushioned, rigid plaster boot (TCC) or of a rigid ankle-foot orthosis, with weightbearing allowed as tolerated. This treatment regimen was associated with a lower incidence of ulcerations (8%) compared to an unprotected weightbearing regimen (31%) in patients with unilateral CN (p?=?0.036). Even overweight patients with stage 1 CN according to Eichenholtz, treated with a TCC that permitted full weightbearing, successfully progressed into therapeutic footwear after an average time of 12 weeks [37]. Furthermore, non-weightbearing treatment may have an unfavorable consequence on the contralateral, unaffected limb in patients with CN, due to increased stress [30]. Clohisy et al reported that the time period to affect the contralateral limb is longer (12 months) in patients with weightbearing treatment compared to a weight-off regimen (4.5 months) [39]. Our investigation showed that the incidence of foot ulcers is higher in bilaterally affected patients compared to unilaterally affected individuals (p?=?0.004). We therefore recommend a weightbearing treatment in a TCC in an acute stage of CN to prevent, or at least defer, progression of the disease with its complications to the contralateral side.
The alternative to a TCC is a pre-fabricated removable walker cast (i.e. Aircast®, DJO Global, Cal, USA or Vacoped®, OPED AG, Cham, Switzerland), which has the advantage of much lower costs compared to a regularly changed custom-made TCC. Use of a TCC for diabetic foot ulcers compared to a removable cast walker or half-shoe showed higher healing percentages and a shorter healing time for the TCC [2, 10, 20].
Although a 6% risk for development of pressure ulcers with the TCC has been reported, the rate of permanent sequelae from cast-related injuries is low (0.25%), and the TCC was rated as a safe modality for protected weightbearing and immobilization of the neuropathic foot [13, 40].
The major disadvantage of a removable, non-custom tailored device is a diminished compliance due to the easy removability of the device by the patient [41, 42]. This may lead to increased local pressure on the skin and, in combination with insensibility, contains an increased risk of ulceration. Compliance with wearing prescribed footwear is low [42, 43]. Only 28% of CN patients wore their removable walker brace full time (23.5 h/day), and non-compliance was shown to lead to a longer bracing period (29?±?19 weeks) [43]. An important attribute of the TCC is that it is not easily removable and therefore has the advantage to enhance compliance [41]. It also seems to curtail activity, which reduces the number of stress cycles on vulnerable skin [41].
The protected weightbearing treatment period in a TCC in our investigation was 20?±?21 weeks for unilaterally affected patients and 22?±?29 weeks for bilaterally affected subjects. Our average duration of treatment corresponds to the findings of Armstrong et al with a period of 18.5?±?10.6 weeks and Christensen et al of 20.1?±?3 weeks [27]. However, they reported a re-casting of the unprotected extremity for a mean of 11.2 weeks in cases of exacerbation or recurrence of CN after reloading, i.e., upon initial cast removal [27, 44]. Bates et al treated 34 patients with a TCC and 12 individuals with a removable cast walker in the presence of contraindications for a TCC for 11 (range: 8 to16.7) months, and 33% had to extend their treatment period to a total duration of 20 (range, 15 to 21) (Bates M, Petrova NL, Edmonds ME: How long does it take to progress from cast to shoes in the management of Charcot osteoarthropathy? Diabetes Foot Study Group of the EASD, unpublished) months due to recurrence of inflammation. In our experience, a protected weightbearing regimen should be maintained as long as signs of inflammation such as redness and warmth are present. In the case of inconclusive clinical signs, we recommend performing an MRI to exclude residual inflammatory sites.
In our assessment, we found a shorter period until definitive treatment was initiated (mean 5 months, range 1–65 months), compared to previously published investigations. Game et al reported a duration of treatment to resolution (mobilized in orthotic or normal shoes) of 10 months (range 2–40 months) in a multicenter, web-based observational study of 288 cases in the UK. Armstrong et al suggested a time to footwear of 7?±?3.6 months in 55 patients with CN [44, 45].
Surgical treatment was performed in cases of chronic ulceration or soft tissue infection to avoid amputation of the limb. In our experience, open surgery on an inflamed CN foot often ends in disastrous results due to infections, bone resorption, or implant loosening [46]. Therefore, it is essential to find the correct timing for such an intervention.
Nevertheless, there are situations where stability of the foot can only be achieved through operative intervention. In these situations, the circular Ilizarov fixator is an excellent treatment option because of the ability to correct multiplanar deformities [47]. Other investigators provide early reconstructive surgery in patients with advanced instability of the foot. Intervention was associated with a benefit compared to secondary operations after non-operative treatment concerning a stable, ulcer- and infection free situation [22]. The goal in CN treatment is a stable foot either by a multi-level arthrodesis or a firm fibrosis, which can be fitted with a custom-made shoe [23, 24]. El-Gafary et al treated 20 patients with CN at Eichenholtz stage 2 and presence of joint subluxations or deformities with repositioning and stabilization by application of an Ilizarov frame with restricted weightbearing [48]. They reported good clinical outcomes with a time to arthrodesis of 18 weeks (range 15–20 weeks) [48]. However, pin site infections in these situations were frequent (15 of 20 patients).
Our study has limitations. We had no measurements of skin temperature, HbA1c, or body mass index at the onset of disease or during the follow-up period. Also, the potential impact of wounds present at initiation of treatment on the primary outcome of new ulcer incidence is not well understood. Further limitations are the retrospective study design and the lack of precise matching of groups. Although our assessment included one of the largest samples available compared to other studies of CN, evaluation of treatment regimens for this disease would benefit from larger, prospective trials with homogenous patient cohorts. Nevertheless, our findings may assist in the decision making and treatment planning for a CN foot.