Background: The controlled ankle motion (CAM) boot has become an integral part of the management of both operative and nonoperative foot and ankle conditions. Similar to casts, CAM boots are used to immobilize the foot and ankle after injury or surgery. However, unlike casts, CAM boots can be readily removed for showering and range of motion (ROM) exercises. While CAM boots are well-designed for ambulation and are frequently utilized in early weightbearing (WB) and early ROM protocols, their usage in non-weightbearing (NWB) protocols is less clear.
Purpose: The purpose of the current study is to determine the patient compliance rate with NWB restriction in a CAM boot after foot/ankle surgery.
Methods: Patients who underwent foot and ankle surgery by a single surgeon and were instructed to be NWB in a CAM boot at two weeks postoperative were enrolled in this study at their six-week postoperative clinic visit. They were given an anonymous questionnaire asking about their level of compliance with the prescribed NWB restriction. The main question of interest asked, “Since you started wearing the CAM boot, how many times have you put any weight on the injured leg while standing or walking?” to which subjects could respond with never, a few times, or frequently. This was termed ‘stated non- compliance’ and the responses were graded as -0, 1, or 2, respectively. If their stated noncompliance was greater than grade 0, they were asked to provide reason(s). Photos of the CAM boot sole and the heel portion was visually inspected for wear and graded as 0, 1, or 2, depending on whether there was a low, medium or high level of wear, respectively. This was termed ‘wear noncompliance’. For any given patient, ‘final noncompliance’ was defined as the higher grade between stated and wear noncompliance. Moderate compliance rate was defined as percentage of patients with a final noncompliance of 0 or 1. Strict compliance rate was defined as the percentage of patients with a final noncompliance grade of 0. Of the 35 patients eligible for the study, 97% responded to the survey. 65% (22/34) of patients were female with a mean age of 54 .8 years.
Results: The moderate compliance was determined to be 91% and strict compliance rate was 29%. There was 53% agreement between stated noncompliance and wear noncompliance. Both cases of grade 2 stated noncompliance were also classified as grade 2 wear noncompliance. In the remaining 16 patients in which stated and wear noncompliance were not in agreement, 12 patients reported grade 1 stated noncompliance but their wear noncompliance was grade 0. The most commonly reported reason for noncompliance was that they tripped and needed to put weight on the operative leg to avoid falling All three cases of grade 2 final noncompliance reported ‘no pain’ as one of their reasons for noncompliance.
Conclusion: In a postoperative foot and ankle patient population, NWB restriction in a CAM boot yields a moderate compliance rate of 91% and strict compliance rate of 29%. CAM boots may be sufficient for more stable fixation constructs such as most ankle fractures. However, surgeries requiring strict NWB compliance such as joint depression type calcaneus fracture and pilon open reduction internal fixation may be more reliably served with casting. Assessment of CAM boot wear pattern can be used to grossly estimate patient compliance and is especially useful for identifying higher levels of noncompliance.
